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LEGAL  (CHEMISTRY. 


A  GUIDE 


DETECTION    OF    POISONS, 
EXAMINATION    OF    TEA,    STAINS,    ETC., 


AS  APPLIED  TO 


CHEMICAL  JURISPRUDENCE. 

TRANSLATED     WITH     ADDITIONS     FROM      THE     FRENCH     OF 

A.  NAQUET, 

Professor  to  the  Faculty  of  Medicine  of  Paris. 
BY 

J.  P.  BATTERSHALL,  NAT.  Sc.  D.,  F.C.S. 


SECOND  EDITION,  REVISED^  WITH  ADDITIONS.        L«T"VvTlY 

NEW  YORK: 

D.   VAN   NOSTRAND,  PUBLISHER, 

23  MURRAY  STREET  AND  27  WARREN  STREET. 

1884. 


COPYRIGHT. 

D.  VAN  NOSTRAND. 
1876. 


PREFACE. 


THE  importance  of  exact  chemical  analysis  in  a  great 
variety  of  cases  which  come  before  the  courts  is  now  fully 
recognized,  and  the  translation  of  this  excellent  little  book  on 
Legal  Chemistry,  by  one  of  the  most  distinguished  French 
Chemists,  will  be  appreciated  by  a  large  class  of  American 
readers  who  are  not  able  to  consult  the  original.  While  it  is 
to  be  regretted  that  the  author  has  not  presented  a  much  more 
complete  work,  there  is  an  advantage  in  the  compact  form  of 
this  treatise  which  compensates,  in  some  degree,  for  its 
brevity. 

The  translator  has  greatly  increased  the  value  of  the  book 
by  a  few  additions  and  his  copious  index,  and  especially  by 
the  lists  of  works  and  memoirs  which  he  has  appended  ;  and 
while  he  could  have  further  increased  its  value  by  additions 
from  other  authors,  we  recognize  the  weight  of  the  considera- 
tions which  induced  him  to  present  it  in  the  form  given  to 
it  by  the  author.  Some  chapters  will  have  very  little  value  in 
this  country  at  this  day,  but  the  translator  could  not,  with 
propriety,  omit  anything  contained  in  the  original. 

C.  F.  CHANDLER. 


PREFACE  TO  THE  SECOND  EDITION. 


THE  principal  change  to  note  in  this  edition  of  the 
LEGAL  CHEMISTRY  is  the  addition  of  a  chapter  on  .Tea 
and  its  Adulteration.  The  general  interest  at  present 
evinced  concerning  this  species  of  sophistication  appeared 
to  call  for  a  simple  and  concise  method  of  examination 
which  would  include  the  requisite  tests  without  entering 
upon  an  exhaustive  treatment  of  the  subject.  The  trans- 
lator's practical  experience  in  the  testing  of  tea  at  the 
United  States  Laboratory  of  this  city  has  enabled  him  to 
make  a  few  suggestions  in  this  regard  which,  he  trusts, 
may  be  of  use  to  those  interested  in  food-analysis.  Nu- 
merous additions  have  also  been  made  to  the  bibliographi- 
cal appendix.  J.  P.  B. 


CONTENTS. 


PAGE 

INTRODUCTION 5 

METHODS  OF  DESTRUCTION  OF  THE  ORGANIC  SUBSTANCES 

By  means  of  Nitric  Acid 8 

"               "   Sulphuric  Acid 9 

"               "    Nitrate  of  Potassa    10 

"    Potassa  and  Nitrate  of  Lime 12 

"              "   Potassa  and  Nitric  Acid 12 

"              "    Chlorate  of  Potassa 13 

"               "    Chlorine 13 

"    Aqua  Regia 14 

Dialysis 15 

DETECTION  OF  POISONS,  THE  PRESENCE  OF  WHICH  is  SUSPECTED. 

Detection  of  Arsenic 17 

Method  used  prior  to  Marsh's  test 17 

Marsh's  test 21 

RaspaiPs  test 29 

ReinscKs  test 30 

Detection  of  Antimony 30 

Flandin  and  Danger's  apparatits 32 

Naquefs  apparatus 34 

Detection  of  Mercury 36 

Smithson's  file 36 

Flandin  and  Danger's  apparatus 37 

Detection  of  Phosphorus 39 

Orftla's  method 39 

MistcherlicK 's  method 40 

Dusarfs  method,  as  modified  by  Blondlot 40 

Frcsenius  and  Neubaicer's  method 42 

Detection  of  Phosphorus  by  means  of  bisulphide  of  carbon.. 43 

Detection  of  Phosphorous  Acid 45 

Estimation  of  Phosphorus 45 

Detection  of  Acids 4^ 

Hydrochloric  Acid 46 

Nitric  "  47 


2  CONTENTS. 

PAGE 

DETECTION  OF  POISONS,  (Continued). 

Sulphuric  Acid      47 

Phosplwric      "         48 

Oxalic             "         s 49 

Acetic              "         49 

Hydrocyanic  "         50 

Detection  of  alkalies  and  alkaline  earths 52 

Detection  of  chlorine,  bromine  and  iodine 54 

Chlorine  and  Bleaching  Chlorides 54 

Bromine 55 

Iodine 56 

Detection  of  Metals 56 

Detection  of  alkaloids  and  some  ill-defined  organic  substances 65 

Stasis  method 65 

"            "      as  modified  by  Otto , 69 

«            «               "           "     Uslar  and  Erdman 70 

Rodger  s  and  Girdivood's  method 71 

Prollius's  method 72 

Graham  and  Hofmaii's  method. 73 

Application  of  Dialysis  in  the  detection  of  Alkaloids 74 

Identification  of  the  Alkaloid. 74 

Identification  of  Digitaline,  Picrotoxine  and  Colchicine 80 

METHOD  TO  BE  EMPLOYED  WHEN  NO  CLEW  TO  THE  NATURE  OF  THE 

POISON  PRESENT  CAN  BE  OBTAINED 85 

Indicative  tests 86 

Determinative  tests 94 

MISCELLANEOUS  EXAMINATIONS 96 

Determination  of  the  nature  and  color  of  the  hair  and  beard 96 

Determination  of  the  color  of  the  hair  and  beard 96 

Determination  of  the  nature  of  the  hair '. 99 

Examination  of  Fire-arms 100 

The  gun  is  provided  -with  a  flint-lock  and  was  charged  with  ordinary 

powder 100 

The  gun  is  not  provided -with  a  flint-lock 103 

Detection  of  human  remains  in  the  ashes  of  a  fire-place 104 

Examination  of  writings 105 

Examination  of  writings,  in  cases  where  a  sympathetic  ink  has  been  used .  no 

Falsification  of  coins  and  alloys 112 


CONTENTS.  3 

PAGE 

MISCELLANEOUS  EXAMINATIONS,  (Continued). 

Examination  of  alimentary  and  pharmaceutical  substances 114 

Flour  and  Bread 114 

Fixed  Oils 128 

a  Olive  Oil  intended  for  table  use 128 

b  Olive  Oil  intended  for  manufacturing  purposes 130 

c  Hemp-seed  Oil 130 

Tea 130 

Milk 137 

Wine 143 

Vznegar 147 

Sulphate  of  Quinine 148 

Examination  of  blood  stains 150 

Examination  of  spermatic  stains 158 

APPENDIX , 163 

Books  of  Toxicology,  etc 163 

Memoirs  on  Toxicology,  etc 168 

INDEX , ,,  187 


BOTANIC/ 


LEGAL    CHEMISTRY. 


The  term  Legal  Chemistry  is  applied  to  that  branch  of  the 
science  which  has  for  its  office  the  solution  of  problems  pro- 
posed in  the  interest  of  Justice.  These  most  frequently  relate 
to  cases  of  poisoning.  When  the  subject  of  the  symptoms  or 
anatomical  lesions  produced  by  the  reception  of  a  poison  is 
under  consideration,  the  services  of  a  medical  expert  are  re- 
sorted to ;  but  when  the  presence  or  absence  of  a  poison  in 
the  organs  of  a  body,  in  the  egesta  of  an  invalid  or  elsewhere 
is  to  be  demonstrated,  recourse  is  had  to  the  legal  chemist. 
Investigations  of  this  character  require  great  practice  in  man- 
ipulation, and,  however  well  the  methods  of  analysis  may  be 
described  in  the  works  on  the  subject,  there  would  be  great 
danger  of  committing  errors  were  the  examination  executed  by 
an  inexperienced  person.  The  detection  of  poisons,  although 
perhaps  the  most  important,  is  not  the  only  subject  that  may 
come  within  the  province  of  the  legal  chemist ;  indeed,  it  would 
be  somewhat  difficult  to  define,  a  priori,  the  multitude  of  ques- 
tions that  might  arise.  In  addition  to  cases  of  supposed  poi- 
soning, the  following  researches  are  most  often  required  : 

1.  The  examination  of  fire-arms. 

2.  The  analysis  of  ashes,  in  cases  where  the  destruction  of 
a  human  body  is  suspected. 


6  LEGAL  CHEMISTRY. 

3.  The  detection  of  alteration  of  writings,  and  of  falsification 
of  coins  and  precious  alloys. 

4.  The  analysis  of  alimentary  substances. 

5.  The  examination  of  stains  produced  by  blood  and  by  the 
spermatic  fluid.  % 

Each  of  these  researches  justly  demands  a  more  ex- 
tended consideration  than  the  limits  of  this  work  would  per- 
mit. The  several  subjects  will  be  treated  as  briefly  as  possible, 
and  at  the  same  time,  so  as  to  convey  an  exact  idea  of  the  meth- 
ods employed,  leaving  to  the  expert  the  selection  of  the  particu- 
lar one  adapted  to  the  case  under  investigation.  We  will  first 
mention  the  methods  used  in  the  search  for  toxical  substances. 
The  poisons  employed  for  criminal  purposes  are  sometimes  met 
with  in  a  free  state,  either  in  the  stomach  or  intestines  of  the 
deceased  person,  or  in  the  bottles  discovered  in  the  room  of 
the  criminal  or  the  victim.  Under  these  circumstances,  it  is 
only  necessary  to  establish  their  identity  by  means  of  their 
chemical  properties,  as  directed  in  the  general  treatises  on 
chemistry,  or  by  their  botanical,  or  zoological  character,  in 
case  a  vegetable  or  animal  poison,  such  as  cantharides,  has  been 
administered.  Examinations  of  this  class  are  extremely  sim- 
ple, the  analysis  of  the  substances  found,  confined  to  a  few  char- 
acteristic reactions,  being  a  matter  of  no  great  difficulty.  We  will 
not  here  dwell  longer  upon  this  subject,  inasmuch  as  the  an- 
alytical methods  used  are  identical  with  those  employed  in 
more  complicated  cases,  with  the  sole  difference  that,  instead  of 
performing  minute  and  laborious  operations  in  order  to  extract 
the  poisons  from  the  organs  in  which  they  are  contained,  with 
a  view  of  their  subsequent  identification,  we  proceed  at  once 
to  establish  their  identity.  The  directions  given  in  regard  to 
complicated  investigations  apply,  therefore,  equally  well  to 
cases  of  a  more  simple  nature.  The  detection  of  a  poison 


INTRODUCTION.  7 

mixed  with  the  organic  substances  encountered  in  the  stomach, 
or  absorbed  by,  and  intimately  united  with  the  tissues  of  the 
various  organs  is  more  difficult.  If,  however,  other  informa- 
tion than  chemical  can  be  obtained,  indicating  the  poison 
supposed  to  be  present,  and  the  presence  or  absence  of  this 
one  poison  is  the  only  thing  to  be  determined,  positive  methods 
exist  which  admit  of  a  speedy  solution  of  the  question. 
When,  on  the  other  hand,  the  chemical  expert  has  not  the 
advantage  of  extraneous  information,  but  is  simply  asked, — 
whether  the  case  be  one  of  poisoning  ? — nothing  being  speci- 
fied as  to  the  nature  of  the  poison  used,  the  difficulty  of  his 
task  is  greatly  increased.  Up  to  the  present  time,  the  works  on 
Toxicology  have,  it  is  true,  given  excellent  special  tests  for  the 
detection  of  particular  poisons  ;  but  none  have  contained  a 
reliable  general  method,  which  the  chemical  expert  could  use 
with  the  certainty  of  omitting  nothing.  Impressed  with 
this  need,  we  proposed,  in  1859,  in  an  inaugural  dissertation 
then  presented  to  the  Faculty  of  Medicine,  a  general  method, 
which,  after  some  slight  modifications,  is  now  reproduced.  The 
special  methods  which  allow  of  the  detection  of  various  indi- 
vidual poisons  will,  however,  first  be  indicated.  In  cases  where 
the  poison  is  mixed  with  organic  matter,  the  latter  must  be 
removed  as  the  first  step  in  the  investigation,  as  otherwise  the 
reactions  characteristic  of  the  poison  searched  for  would  be 
obscured.  When  the  poison  itself  is  an  organic  substance,  this 
separation  is  effected  by  processes  modified  according  to  the 
circumstances.  If  the  detection  or  isolation  of  a  metallic 
poison  is  to  be  accomplished,  the  most  simple  method  consists 
in  the  destruction  of  the  organic  substances.  The  various 
methods  for  effecting  this  decomposition  will  now  be  described. 


I. 


METHOD*    OF    DESTRUCTION    OF    THE    ORGANIC 

SUBSTANCES. 


BY   MEANS   OF    NITRIC   ACID. 

In  order  to  destroy  the  organic  matters  by  this  process,  a 
quantity  of  nitric  acid  equal  to  one  and  a  half  times  the 
weight  of  the  substances  taken  is  heated  i-n  a  porcelain 
evaporating  dish,  the  amount  of  acid  being  increased  to  four 
or  six  times  that  of  the  organic  substances  if  these  comprise 
the  brains  or  liver.  As  soon  as  the  acid  becomes  warm,  the 
suspected  organs,  which  have  previously  been  cut  into  pieces, 
are  added  in  successive  portions :  the  organs  become  rapidly 
disintegrated,  brownish-red  vapors  being  evolved.  When  all 
is  brought  into  solution,  the  evaporation  is  completed  and  the 
carbonaceous  residue  obtained  separated  from  the  dish  and 
treated  either  with  water,  or  with  water  acidulated  with  nitric 
acid,  according  to  the  nature  of  the  poison  supposed  to  be 
present. 

Several  objections  to  this  method  exist,  the  most  serious  of 
which  is  based  upon  the  fact  that  the  carbonaceous  residue, 
containing,  as  it  may,  nitric  acid,  readily  takes  fire  and  may 


DESTRUCTION  OF  THE  ORGANIC  SUBSTANCES.    9 

therefore  be  consumed,  or  projected  from  the  vessel.  This 
objection  is  a  grave  one,  and  is  not  always  entirely  removed 
by  the  continual  stirring  of  the  materials.  According  to  M. 
Filhol,  the  addition  of  10  to  15  drops  of  sulphuric  acid  to  the 
nitric  acid  taken  obviates  the  difficulty  ;  not  having  personally 
tested  the  question  we  cannot  pronounce  upon  it.  If  it  be 
the  case,  this  process  is  an  advantageous  one,  as  it  is  not 
limited  in  its  application,  but  can  be  used  in  the  separation  of 
all  mineral  poisons. 

BY   MEANS   OF   SULPHURIC   ACID. 

The  organic  matter  to  be  decomposed  is  heated  with 
about  one-fifth  of  its  weight  of  concentrated  sulphuric  acid, 
the  complete  solution  of  the  materials  being  thus  accomplished. 
The  excess  of  acid  is  next  removed  by  heating  until  a  spongy 
carbonaceous  mass  remains.  The  further  treatment  of  this 
residue  depends  upon  the  nature  of  the  poison  supposed  to 
be  present.  If  the  sulphate  of  the  suspected  poison  is  a 
soluble  and  stable  compound,  the  residue  is  directly  treated 
with  water ;  if,  on  the  contrary,  there  is  reason  to  think  that 
the  sulphate  has  suffered  decomposition,  the  mass  is  taken  up 
with  dilute  nitric  acid ;  if,  finally,  the  presence  of  arsenic  is 
suspected,  the  residue  is  moistened  with  nitric  acid,  in  order  to 
convert  this  body  into  arsenic  acid.  The  acid  is  afterwards 
removed  by  evaporation,  the  well  pulverized  residue  boiled 
with  distilled  water,  and  the  solution  then  filtered. 

This  method,  when  applied  in  the  detection  of  arsenic,  is 
objectionable  in  that  the  carbonaceous  residue,  in  contact  with 
sulphuric  acid,  almost  invariably  contains  sulphurous  acid, 
detected  by  means  of  permanganate  of  potassa.  This  acid, 
being  reduced  in  the  presence  of  hydrogen,  would  cause  the 
formation  of  insoluble  sulphide  of  arsenic,  and  in  this  way 

i* 


10  LEGAL  CHEMISTRY. 

prevent  the  detection  of  small  amounts  of  arsenic  by  the  use 
of  Marsh's  apparatus.  M.  Gaultier  de  Claubry,  indeed,  states 
that  he  has  not  been  able  to  detect  the  presence  of  sulphurous 
acid  in  the  carbonaceous  residue ;  but  one  affirmative  result 
would,  in  this  case,  outweigh  twenty  negative  experiments.  A 
further  objection  to  this  process  consists  in  the  fact  that  the 
materials  to  be  destroyed  almost  always  contain  chlorides, 
which,  in  presence  of  sulphuric  acid  and  an  arsenical  com- 
pound, might  determine  the  formation  of  chloride  of  arsenic, 
a  volatile  body,  and  therefore  one  easily  lost.  This  difficulty 
is  doubtless  of  a  less  serious  nature  than  the  preceding,  as 
the  operation  can  be  performed  in  a  closed  vessel  provided 
with  a  receiver  which  admits  of  the  condensation  of  the 
evolved  vapors  ;  but  even  then  the  process  would  be  prolonged. 
The  above  method  is  still  again  objectionable  on  account  of 
its  too  limited  application,  it  being  serviceable  almost  exclu- 
sively in  cases  where  the  poisoning  has  been  caused  by  ar- 
senic, for,  if  applied  in  other  instances,  a  subsequent  treat- 
ment would  be  necessary  in  order  to  redissolve  the  metal 
separated  from  its  decomposed  sulphate. 

BY   MEANS   OF   NITRATE   OF   POTASSA. 

This  method  was  formerly  executed  as  follows  :  Nitrate 
of  potass  a  was  fused  in  a  crucible,  and  the  substances  to  be 
destroyed  added  in  small  portions  to  the  fused  mass.  The 
organic  matter  soon  acquired  a  pure  white  color  •  owing,  how- 
ever, to  the  imperfect  admixture  of  the  organic  matter  with  the 
salt  used  for  its  decomposition,  it  was  necessary  to  take  a 
large  excess  of  the  latter. 

The  following  process,  suggested  by  M.  Orfila,  remedies 
this  inconvenience  :  The  organs  are  placed  in  an  evaporating 
dish,  together  with  one  tenth  of  their  weight  of  caustic  potassa, 


DESTRUCTION  OF  THE  ORGANIC  SUBSTANCES.  1 1 

and  a  quantity  of  water  varying  with  the  weight  of  the  sub- 
stances taken.  An  amount  of  nitrate  of  potassa  equal  to 
twice  the  weight  of  the  organic  matter  is  next  added,  and  the 
mixture  evaporated  to  dryness.  The  residue  is  then  thrown 
by  fragments  into  a  Hessian  crucible  heated  to  redness,  the 
portions  first  taken  being  allowed  to  become  perfectly  white 
before  more  is  added. 

Whichever  process  has  been  employed,  the  fused  mass  is 
decanted  into  a  procelain  crucible,  which  has  previously  been 
heated  in  order  to  avoid  danger  of  breakage.  The  portion 
remaining  in  the  vessel  is  taken  up  by  boiling  with  a  small 
quantity  of  distilled  water,  and  the  solution  so  obtained  like- 
wise added  to  the  crucible.  The  mass  is  then  heated  with 
sulphuric  acid  until  all  nitrous  fumes  are  expelled,  as  these 
could  give  rise  to  an  explosion,  when,  in  the  search  for 
arsenic,  the  substance  is  introduced  into  Marsh's  apparatus. 
As  soon  as  the  nitric  acid  is  completely  expelled,  the  liquid  is 
allowed  to  cool ;  the  greater  portion  of  the  sulphate  of  potassa 
formed  now  separating  out  in  crystals.  The  fluid  is  next 
filtered  and  the  crystalline  salt  remaining  on  the  filter, 
washed,  at  first  with  a  little  distilled  water,  then  with  absolute 
alcohol,  which  is  subsequently  removed  from  the  filtrate  by 
boiling.  This  method  is  scarcely  applicable  otherwise  than 
in  the  detection  of  arsenic,  as  in  other  instances  the  presence 
of  a  large  amount  of  sulphate  of  potassa  would  be  liable  to 
affect  the  nicety  of  the  reactions  afterwards  used.  Its  appli- 
cation, even  in  the  search  for  arsenic,  is  not  to  be  strongly 
recommended ;  on  the  contrary,  the  separation  of  the  potassa 
salt  by  filtration  is  indispensable,  as  otherwise  a  double 
salt  of  zinc  and  potassium,  which  might  be  formed,  being 
deposited  upon  the  zinc  used  in  Marsh's  apparatus,  would 
prevent  the  disengagement  of  hydrogen,  and  every  chemist 


I2  LEGAL  CHEMISTRY. 

is  too  well  aware  of  the  difficulty  of  thoroughly  washing  a  pre- 
cipitate, not  to  fear  the  possible  loss  of  arsenic  by  this 
operation. 

BY   MEANS   OF    POTASSA   AND    NITRATE    OF    LIME. 

In  this  method  the  organic  materials  are  heated  with 
water  and  10  to  15  per  cent,  of  caustic  potassa.  As  soon 
as  disintegration  is  completed,  nitrate  of  lime  is  added,  and 
the  mixture  evaporated  to  dryness.  A  glowing  coal  is  then 
placed  upon  the  carbonaceous  residue  obtained :  the  mass, 
undergoing  combustion,  leaves  a  perfectly  white  residue.  This 
residue  dissolves  in  hydrochloric  acid  to  a  clear  fluid  which 
is  then  examined  for  poisons. 

The  above  process  possesses  the  undeniable  advantage  of 
completely  destroying  the  organic  substances,'  at  the  same 
time  avoiding  the  introduction  of  sulphate  of  potassa,  the 
presence  of  which  impairs  the  usefulness  of  the  preceding 
method  ;  but  it  necessitates  the  presence  of  numerous  foreign 
bodies  in  the  substance  to  be  analysed,  and  this  should  be 
avoided.  The  absolute  purity  of  reagents  is  not  always  to  be 
attained,  and  the  results  of  an  analysis  are  the  more  certain, 
in  proportion  as  they  are  less  numerous  and  more  easily 
purified. 

BY   MEANS   OF    POTASSA   AND   NITRIC   ACID. 

It  has  been  proposed,  instead  of  using  nitrate  of  lime,  to 
dissolve  the  organic  matter  in  potassa  and  then  saturate  the 
fluid  with  nitric  acid.  This  method  is  evidently  more  com- 
plicated than  the  simple  treatment  with  nitrate  of  potassa,  and 
possesses,  moreover,  no  advantages  over  the  latter  process. 


DESTRUCTION  OF  THE  ORGANIC  SUBSTANCES.  13 

BY   MEANS   OF   CHLORATE   OF   POTASSA. 

The  organic  materials  are  treated  with  an  equal  weight  of 
pure  hydrochloric  acid,  and  water  added,  so  as  to  form  a  clear 
pulp.  This  being  accomplished,  two  grammes  of  chlorate  of 
potassa  are  added  to  the  mixture  at  intervals  of  about  five 
minutes.  The  fluid  is  next  filtered,  and  the  insoluble  residue 
remaining  on  the  filter  washed  until  the  wash-water  ceases  to 
exhibit  an  acid  reaction.  The  filtrate  is  then  evaporated,  an 
aqueous  solution  of  sulphurous  acid  added,  until  the  odor  of 
this  reagent  remains  distinctly  perceptible,  and  the  excess  of 
the  acid  removed  by  boiling  the  solution  for  about  an  hour. 
The  fluid  is  now  adapted  to  further  examination  for  arsenic, 
or  other  metallic  poisons. 

This  method  is  one  of  the  best  in  use,  both  chlorate  of 
potassa  and  hydrochloric  acid  being  reagents  easily  procured 
in  a  state  of  great  purity  ;  their  use,  however,  is  liable  to  the 
objection  that  they  convert  silver  and  lead  into  insoluble 
chlorides. 

BY   MEANS    OF   CHLORINE. 

M,  Jacquelain  suggests,  in  the  search  for  arsenic,  the 
decomposition  of  the  organic  matters  by  means  of  a  current  of 
chlorine,  and  recommends  the  following  process  :  The  organic 
substances  are  bruised  in  a  mortar  and  then  macerated  with 
•water.  The  fluid  so  obtained,  in  which  the  organic  matter  is 
held  suspended,  is  next  placed  in  a  flask  into  which  a  current 
of  chlorine  is  passed  until  all  the  organic  matter  is  deposited 
in  colorless  flakes  on  the  bottom  of  the  vessel.  The  flask  is 
then  well  closed  and  allowed  to  stand  for  24  hours,  when  the 
odor  of  the  gas  should  still  be  perceptible.  The  fluid  is  now 
filtered,  the  filtrate  concentrated  by  heating  in  a  vessel  which 


1 4  LEGAL  CHEMISTRY.          • 

permits  of  the  preservation  of  the  volatile  chloride  of  arsenic 
possibly  present,  and  then  examined  for  poisons. 

This  process  fails  to  possess  the  degree  of  generality  desir- 
able, and  presents  the  disadvantage  of  requiring  considerable 
time  for  its  execution. 

BY   MEANS   OF  AQUA   REGIA. 

This  method  is  exceedingly  simple  :  Aqua  regia  (a  mixture 
of  two  parts  of  hydrochloric  and  one  part  of  nitric  acids)  is 
placed  in  a  tubular  retort  provided  with  a  receiver,  and  the 
organic  materials,  which  have  previously  been  cut  into  small 
pieces,  added  ;  the  reaction  commences  immediately ;  if  it  is  not 
sufficiently  active,  it  is  accelerated  by  a  gentle  heat :  lively 
effervescence  now  occurs,  and  the  destruction  of  all  non-olea- 
ginous substances  is  soon  accomplished.  The  latter  sub- 
stances alone  are  not  immediately  decomposed  by  aqua  regia, 
which  attacks  them  only  after  prolonged  action.  As  soon  as 
the  operation  is  concluded,  the  apparatus  is  removed  from 
the  fire  and  taken  apart.  The  fluid  condensed  in  the  receiver 
is  added  to  that  remaining  in  the  retort,  and  the  whole 
thoroughly  cooled  in  an  open  dish.  The  fatty  matters  now 
form  a  solid  crust  upon  the  surface  of  the  fluid,  which  is  re- 
moved and  washed  with  distilled  water,  and,  the  washings 
being  added  to  the  rest  of  the  solution,  ihe  latter  is  directly 
examined  for  metallic  poisons.  It  is  recommended  by  Gaultier 
de  Claubry,  in  cases  where  the  detection  of  arsenic  is  de- 
sired, to  saturate  and  afterwards  boil  the  suspected  fluid  with 
sulphuric  acid,  in  order  to  remove  the  nitric  and  hydro- 
chloric acids  present. 


DESTRUCTION  OF  THE  ORGANIC  SUBSTANCES.  15 


DIALYSIS. 

The  application  of  the  dialytic  method  was  first  proposed 
by  Graham.  By  its  use  we  are  enabled  to  distinguish  between 
two  large  classes  of  bodies,  viz.,  colloids  and  crystalloids. 
Albumen,  gelatine,  and  analogous  substances  are  typical  of 
colloid  bodies  ;  crystalloid  substances,  on  the  other  hand,  are 
those  that  are  capable  of  crystallization,  either  directly  or  in 
their  compounds,  or,  in  case  they  are  fluids,  would  possess  this 
property  when  brought  to  the  solid  state.  Graham  discovered 
that  when  an  aqueous  solution  containing  a  mixture  of  colloid 
and  crystalloid  substances  is  placed  in  a  vessel  having  for  its 
bottom  a  piece  of  parchment  or  animal  membrane,  and  this  is 
immersed  in  a  larger  vessel  filled  with  water,  all  of  the 
crystalloids  contained  in  the  first  vessel  transverse  the  porous 
membrane  and  are  to  be  found  in  the  larger  vessel,  the  col- 
loid bodies  being  retained  above  the  membrane.  The  organic 
matter  to  be  eliminated  in  toxicological  researches  being  col- 
loids, and  the  poisons  usually 
employed  being  crystalloids, 
the  value  of  dialysis  as  a 
method  of  separation  is  evi- 
dent. The  process  is  exe- 
cuted as  follows  : 

A  wooden, — or  better,  a 
gutta-percha— cylinder  (Fig.i), 
5  cubic  centimetres  in  height 
and  from  20  to  25  c.  c.  in 
diameter,  is  employed.  A 
piece  of  moistened  parchment 
is  securely  attached  to  one  of 
the  openings  of  the  cylinder,  F;g. ,. 


i6 


LEGAL  CHEMISTRY. 


which,  upon  drying,  shrinks  and  completely  closes  the  aper- 
ture.   If  its  continuity  becomes  impaired,  the  pores  of  the  mem- 
brane should  be  covered  with  the  white  of  an  egg  which  is 
subsequently  coagulated  by  the   application  of  heat      The 
organs    previously   cut   into    small  pieces,  or    the  materials 
found  in  the  alimentary  canal,  etc.,  after  having  been  allowed 
to  digest  for  24  hours  in  water   at  32°* — or,  in  dilute  acids,  if 
the  presence  of  an  alkaloidis  suspected, — are  then  placed  in  the 
upper  vessel,  which  is  termed  the  dialyser.     The  whole  should 
form  a  layer  not  over  2  cubic  centimetres  in  height.     Tli£ 
dialyser  is  next  placed  in  the  larger  vessel  filled  with  distilled 
water.     In  about  24  hours  three-quarters  of  the  crystalloid 
substances  present   will  have  passed  into  the  lower  vessel. 
The  solution  is  then  evaporated   over  a 
water-bath,    and    submitted    to    analysis. 
The  portion  remaining   in  the  dialyser  is 
decomposed  by  one  of  the  methods  pre- 
viously described,  in  order  to  effect  the 
detection  of    any  poisonous    substances 
possibly  present.      Instead  of  the  above 
apparatus,  the  one  represented  in  Fig.   2 
can  be  employed.    The  fluid  under  exam- 
ination is  placed  in  a  bell-shaped  jar,  open 
at  the  top  and  closed  below  with  a  piece 
of  parchment,  which  is   then   suspended 
in  the  centre   of  a  larger  vessel  contain- 
ing water.     In  other  respects  the  opera- 
tion is  performed  in  the   same  manner 
as  with  the  apparatus  represented  in  Fig.  i. 

*  The  degrees  of  temperature  given  in  the  text  refer  to  the  centigrade 
Thermometer  ;  their  equivalents  on  the  Fahrenheit  scale  can  be  obtained 
by  means  of  the  formula : 

=F°.— Trans. 


Fig.  2. 


II. 


DETECTION    OF    POISONS,    THE    PRESENCE    OF 
\VIIM  II    IS    SUSPECTED. 


DETECTION  OF  ARSENIC. 

IT  is  frequently  required,  in  chemical  jurisprudence,  to  in- 
stitute a  search  for  arsenic  in  the  remains  of  a  deceased  per- 
son, whose  death  is  supposed  to  have  been  caused  by  the 
reception  of  a  poison.  Under  these  circumstances  the  poison 
is  mixed  with  a  mass  of  substances  which  would  obscure  its 
characteristic  properties,  and  it  becomes  necessary,  in  order  to 
accomplish  its  identification,  to  isolate  it,  and  then,  by  de- 
cisive reactions,  determine  its  character.  Three  methods 
exist  which  permit  of  this  result ;  they  are  : 

i st.  The  method  used  prior  to  Marsh's  test. 

2nd.  Marsh's  test. 

3rd.  A  method  more  recent  than  Marsh's,  proposed  by  M. 
Raspail. 

METHOD   USED   PRIOR  TO   MARSH'S   TEST. 

The  materials  supposed  to  contain  arsenic  are  boiled  in 
water  which  has  been  rendered  strongly  alkaline  by  the  ad- 
diton  of  pure  potassa.  The  fluid  is  then  filtered,  an  excess 


1 8  LEGAL  CHEMISTRY. 

of  hydrochloric  acid  added,  and  a  current  of  sulphuretted 
hydrogen  conducted  through  it.  If  arsenic  be  present  in  the 
suspected  fluid,  it  is  soon  precipitated  as  a  yellow  sulphide. 
In  dilute  solutions  the  formation  of  the  precipitate  fails  to 
take  place  immediately,  and  only  a  yellow  coloration  of  the 
fluid  is  perceptible  ;  upon  slightly  boiling  the  solution,  how- 
ever, the  precipitation  of  the  sulphide  is  soon  induced.  The 
precipitate  is  collected  on  a  filter,  well  washed  with  boiling 
water,  and  then  removed,  if  present  in  a  quantity  sufficient  to 
admit  of  this  operation.  It  is  next  dissolved  in  ammonia,* 
and  the  solution  so  obtained  subsequently  evaporated  to  dry- 
ness  on  a  watch-glass.  The  residue  of  sulphide  of  arsenic 
is  placed  in  a  tube  closed  at  one  end  containing  nitrate  of 
potassa  in  a  state  of  fusion  :  it  is  decomposed  by  this  treat- 
ment into  a  mixture  of  sulphate  and  arsenate  of  potassa,  the 
reaction  being  completed  in  about  fifteen  minutes.  The  mix- 
ture is  now  dissolved  in  water,  and  lime  water  added  to  the 
solution  :  a  precipitate  of  arsenate  of  lime  is  formed,  which  is 
separated  from  the  fluid  by  filtration,  dried,  mixed  with  charcoal, 
and  introduced  into  a  second  tube.  A  few  pieces  of  charcoal 
are  then  placed  in  the  tube  adjoining  the  mixture  and  ex- 
posed to  a  red  heat,  the  part  of  the  tube  containing  the 
arsenical  compound  being  also  heated.  By  this  operation 
the  arsenic  acid  is  reduced  to  arsenic,  which  is  deposited  upon 
the  cold  portion  of  the  tube  in  the  form  of  a  metallic  mirror. 
This  mirror  is  then  identified  by  subsequent  reactions.  The 
method  just  described  is  no  longer  in  use,  although  the  pre- 
cipitation of  the  arsenic  by  sulphuretted  hydrogen  is  still 
often  resorted  to  in  its  separation  from  the  other  metals  with 
which  it  may  be  mixed.  The  destruction  of  the  organic  sub- 

*The  sulphur,   usually  accompanying  the  precipitate  of  sulphide   of 
arsenic,  is  insoluble  in  ammonia. —  Trans. 


DETECTION  OF  ARSENIC.  lg 

stances  is,  however,  accomplished  by  means  of  chlorate  of 
potassa  and  hydrochloric  acid.  To  insure  the  complete  pre- 
cipitation of  the  arsenic,  it  is  advisable  to  conduct  sulphur- 


Fig-  3. 

etted  hydrogen  through  the  solution,  at  a  temperature  of  70° 
for   twelve    hours,  and  then    allow  the   fluid  to  remain  in    a 


20  LEGAL  CHEMISTRY. 

moderately  warm  place,  until  the  odor  of  the  gas  is  no  longer 
perceptible,  the  vessel  being  simply  covered  with  a  piece  of 
paper.  The  precipitate  is  next  freed  from  the  other  metals 
possibly  present,  as  directed  in  the  general  method  of  analysis, 
collected  on  a  filter,  and  dissolved  in  ammonia.  The 
ammoniacal  solution  is  evaporated  on  a  watch 
crystal,  as  previously  described,  and  the  residuary 
sulphide  reduced  to  metallic  arsenic.  This  reduc- 
tion is  effected  by  a  process  somewhat  different  from 
the  one  previously  mentioned :  the  residue  is  fused,  in 
a  current  of  carbonic  acid  gas,  with  a  mixture  of  car- 
bonate of  soda  and  cyanide  of  potassium.  The  ap- 
paratus employed  is  represented  in  Fig.  3  :  a,  is  an  ap- 
paratus producing  a  constant  supply  of  carbonic  acid. 
Upon  opening  Mohr's  clamp,  g,  the  gas  passes  into 
the  flask  h,  which  contains  sulphuric  acid ;  it  is  then 
conducted,  by  means  of  the  tube  /,  into  the  reduction 
tube  k,  which  has  an  interior  diameter  of  8  mm. 
This  tube  is  represented,  in  half  size,  in  Fig  4. 

The    reduction    is    performed  as   follows :     The 
.  ^  sulphide  of  arsenic  is  ground  in  a  small  mortar,  pre- 
53  viously  warmed,  together  with  12  parts  of  a  mixture 
consisting  of  3  parts  of  carbonate  of  soda  and  i  part 
of  cyanide  of  potassium,    both  salts  being  perfectly 
dry.       The  powder  thus  obtained  is  placed   upon  a 
piece  of  paper  rolled  in  the  form  of  a  gutter,  and  in- 
troduced into  the  reduction  tube.     The  latter  is  then 
turned  half  round  its  axis,  so  as  to  cause  the  mixture 
to  fall  in  de  without   soiling  the   other  parts  of  the 
tube.    The  paper  is  now  withdrawn  and  the  apparatus 
Fig.  4.     mounted.      Upon  opening  the  clamp  g,  and  strongly 
heating  the  mixture  by  either  the  flame  of  a  gas  or  an  alcohol 


DETECTION  OF  ARSENIC.  21 

lamp,  a  mirror-like  ring  of  metallic  arsenic  is  deposited  at  h, 
if  this  poison  be  present  in  the  substances  under  examination. 
When  the  coating  is  too  minute  to  permit  of  perfect  identifi- 
cation, it  should  be  driven  by  heat  to  a  thinner  part  of  the 
tube;  in  this  way  it  is  rendered  easily  visible,  being  condensed 
upon  a  smaller  space. 

The  above  process  possesses  the  advantage  of  not  allowing 
arsenic  to  be  confounded  with  any  other  body ;  it  also  per- 
mits of  a  quantitative  estimation  of  the  poison  present.  For 
this  purpose,  it  is  only  necessary  to  previously  weigh  the  watch- 
crystal,  upon  which  the  ammoniacal  solution  of  sulphide  of 
arsenic  was  evaporated,  and  to  determine  its  increased  weight 
after  the  evaporation ;  the  difference  of  the  two  weighings 
multiplied  by  0.8049,  gives  the  corresponding  weight  of 
arsenious  acid,  and  by  0.6098.  the  weight  of  the  correspond- 
ing amount  of  metallic  arsenic. 

MARSH'S  TEST. 

Marsh's  test  is  based  upon  the  reduction  of  arsenioift  and 
arsenic  acids  by  nascent  hydrogen,  and  the  subsequent  trans- 
formation of  these  bodies  into  water  and  arsenetted  hydrogen, 
a  compound  from  which  the  arsenic  can  be  readily  isolated. 
When  pure  hydrogen  is  generated  in  a  flask  having  two  open- 
ings, one  of  which  is  provided  with  a  perforated  cork  through 
which  a  safety-tube  passes,  the  other  with  a  tube  bent  at  a 
right  angle  and  drawn  out  to  a  small  point  at  the  free  extrem- 
ity, the  evolved  gas,  if  ignited,  burns  with  a  pale  non-luminous 
flame.  The  air  should  be  completely  expelled* from  the  appar- 
atus before  igniting  the  gas.  Upon  bringing  a  cold  porcelain 
saucer  in  contact  with  the  point  of  the  flame,  only  water  is 
formed.  If,  however,  a  small  quantity  of  a  solution  containing 


22  LEGAL  CHEMISTRY. 

arsenious  or  arsenic  acids  is  introduced  into  the  apparatus 
by  means  of  the  safety-tube,  arsenetted  hydrogen  is  produced. 
This  gas  burns  with  a  bright  flame,  yielding  fumes  of  arseni 
ous  acid.  In  case  a  large  amount  of  the  poison  is  present,  it 
can  be  recognized  by  the  appearance  of  the  flame,  and  by  in- 
clining a  glass  tube  towards  it  upon  which  a  portion  of  the 
arsenious  acid  becomes  deposited.  These  indications  are, 
however,  not  distinguishable  in  presence  of  only  a  small  amount 
of  arsenic,  and  the  following  distinctive  properties  of  the  gas 
should  be  verified  : 

i  st.  At  an  elevated  temperature  it  is  decomposed  into  its 
two  constituent  elements. 

2nd.  The  combustibility  of  the  constituents  differs  :  the 
arsenic  being  less  combustible  than  the  hydrogen,  begins  to 
burn  only  after  the  complete  consumption  of  the  latter  body  has 
taken  place.  For  this  reason  the  flame  (Fig.  5)  is  composed 

of  a  dark  portion  O  and  a  lu- 
minous portion  I,  which  sur- 
rounds the  first.  The  maximum 
temperature  exists  in  O  at  the 
point  of  union  of  the  two  parts 
of  the  flame.  Owing  to  an  in- 
Fig.  s-  sufficient  supply  of  oxygen,  the 

complete  combustion  of  the  arsenic  in  this  part  of  the 
flame  is  impossible,  and  if  it  be  intersected  by  the  cold  sur- 
face A  J5,  that  body  is  deposited  as  a  brown  spot,  possessing 
a  metallic  lustre.  The  metallic  deposit  originates,  therefore, 
from  the  decomposition  of  the  arsenetted  hydrogen  by  heat 
and  from  its  ^incomplete  combustion.  If  the  spot  is  not 
large,  it  fails  to  exhibit  a  metallic  lustre ;  an  experienced 
chemist,  however,  will  be  able  to  identify  it  by  the  aid  of  proper 
tests.  Spots  are  sometimes  obtained  when  the  substance 


DETECTION  OF  ARSENIC.  23 

under  examination  does  not  contain  the  least  trace  of  arsenic. 
These  may  be  caused  by  antimony  or  by  a  portion  of  the 
zinc  salt  in  the  generating  flask  being  carried  over  by  the 
gaseous  current.  This  difficulty  is  remedied  by  giving  the  ap 
paratus  the  form  represented  in  Fig.  6.  A  is  the  flask  in 


Fig.  6. 

which  the  gas  is  generated.  The  delivery-tube /connects  with 
a  second  tube  Jf,  rilled  with  asbestus  or  cotton ;  this  is  united 
by  means  of  a  cork  with  a  third  tube  C,  made  of  Bohemian 
glass.  The  latter  tube  is  quite  long,  and  terminates  in  a  jet 
at  its  free  end,  enclosed  in  tin-foil;*  it  passes  through  the 
sheet-iron  furnace  Jt,  supported  upon  G.  The  screen  D  pro- 
tects the  portion  D  E  of  the  tube  C  from  the  heat.  The  gas 
disengaged  is  ignited  at  E  and  the  porcelain  dish  P  is  held  by 
the  hand  in  contact  with  the  flame.  The  apparatus  being 
mounted,  zinc,  water  and  some  sulphuric  acid  are  placed  in  the 

*  The  fusing  of  the  point  of  the  tube  is  also  prevented  by  platinizing 
it.  The  tube  is  drawn  out,  its  end  roughened  by  filing,  and  then  immersed 
in  solution  of  bichloride  of  platinum,  so  that  a  drop  or  two  of  the  fluid 
adheres.  The  point,  upon  heating,  now  acquires  a  fine  metallic  lustre,  and 
by  repeating  the  operation  a  few  times  a  good  coating  of  platinum  is  pro- 
duced both  on  the  exterior  and  interior  of  the  tube. —  Trans. 


24  LEGAL  CHEMISTRY. 

generating  flask,*  and  the  solution  containing  arsenious  acid 
added :  the  evolution  of  gas  commences  immediately.  The 
tube  ^"serves  to  retain  any  liquids  that  may  be  held  suspend- 
ed. The  gas  then  passes  through  the  part  C  D  of  the  tube  C, 
which  is  heated  by  placing  a  few  live  coals  upon  the  furnace  R. 
The  greater  portion  of  the  arsenetted  hydrogen  is  decomposed 
here,  and  is  deposited  on  the  cold  part  of  the  tube,  in  a  mir- 
ror-like ring.  The  small  quantity  of  gas  that  escapes  decom- 
position, if  ignited  at  £,  produces  a  metallic  spot  on  the 
dish  P.  In  order  to  determine  that  the  spots  are  due  to  the 
presence  of  arsenic,  and  not  produced  by  antimony,  the  fol- 
lowing tests  should  be  applied : 

1.  The  color  of  the  spots  is  distinctive :  arsenical  spots  are 
brown   and  exhibit   a  metallic   lustre,  whereas  those  origina- 
ting from  antimony  possess  a  black  color,  especially  near  their 
border.      This  difference  is,  however,  not  perceptible  when 
the  deposits  have  a  large  surface. 

2.  If  the  mirror  be  arsenical,  it  is  readily  volatilized  from 
one  part  of   the  tube  to  another,  when  the  latter  is  heated, 
and  a  current  of  hydrogen,  or  carbonic  acid  gas   made  to 
pass  through  it.  Spots  that  are  due  to  the  presence  of  antimony 
are  much  less  volatile. 

3.  If  the  tube  is  held  in  an  inclined  position  so  that  a  cur- 
rent of  air  traverses  it,  and  the  part  containing  the  arsenical 
mirror  heated,   the   arsenic   oxidizes   and   arsenious   acid   is 
sublimed   and  deposited  higher  up  in  the  tube  in  the  form 
of  a  ring,  which  exhibits  octahedral  crystals   when  examined 
•with  a  magnifying  glass.     This  ring  should  be  further  tested 
as  follows : 

a.  If  it  is  dissolved  in  a  drop  of  hydrochloric  acid  and  a  so- 

*  The  addition  of  a  few  drops  of  solution  of  bichloride  of  platinum 
to  the  mixture  of  zinc,  water  and  sulphuric  acid  is  advisable. —  Trans 


DETECTION  OF  ARSENIC.  25 

lution  of  sulphuretted  hydrogen  added,  a  yellow  precipitate  of 
sulphide  of  arsenic  is  formed.  This  compound  is  soluble  in 
ammonia  and  in  alkaline  sulphides,  but  insoluble  in  hydro- 
chloric acid. 

b.  If  the  ring  is  dissolved  in  pure  water  and  an  am- 
moniacal  solution  of  sulphate  of  copper  added,  a  beautiful 
green  precipitate  ("  Scheele's  green  "),  consisting  of  arsenite  of 
copper,  is  produced. 

4.  When  produced   by  arsenic  the   spots   are  soluble  in 
nitric  acid,  and  upon  evaporating  the  solution  so  obtained  to 
dryness,  a  residue  of  arsenic  acid,  which  is  easily  soluble  in 
water,  remains.     If  an  ammoniacal  solution  of  nitrate  of  silver 
is  added  to  the  aqueous  solution  of  the  residue,  a  brick-red 
precipitate   is   produced.     Spots  consisting  of  antimony  give, 
when  treated  with  nitric  acid,  a  residue  of  an  intermediate 
oxide,  insoluble  in  water. 

5.  Upon   treating  the  spots   with  a   drop  of  solution   of 
sulphide  of  ammonium,  the  sulphide  of  the  metal  present  is 
formed  :  if  sulphide  of  arsenic  is  produced  its  properties,  as  enu- 
merated above,  can  be  recognized.      It  may  be  added  that  the 
sulphide  of  antimony  formed  is  soluble  in  hydrochloric  acid, 
and  possesses  an  orange  red  color,  whereas  sulphide  of  arsenic 
is  yellow. 

6.  When   spots   originating  from  arsenic  are  treated  with 
a  solution  of  hypochlorite  of  soda  (prepared  by  passing  chlo- 
rine into  solution  of  carbonate  of  soda),  they  are  immediately 
dissolved ;  if,  on  the  other  hand,  they  are  produced  by  anti- 
mony, they  remain  unaltered  by  this  treatment. 

Such  are  the  properties  exhibited  by  soluble  compounds  of 
arsenic  when  treated  by  Marsh's  process  ;  the  following  pre- 
cautions are,  however,  necessary  when  this  test  is  made  use  of 
in  medico-legal  examinations. 

2 


26  LEGAL  CHEMISTRY. 

1.  If  small   white  gritty  particles,   resembling  arsenious 
acid,  are  discovered   in  the  stomach  or  intestines,  they  are 
directly  introduced  into  Marsh's  apparatus.     When  this  is  not 
the  case,  the  destruction  of  the  organic  matter  is  indispen 
sable  even  though,  instead  of  the  organs  themselves,  the  con- 
tents of  the  alimentary  canal  are  taken.   In  the  latter  instance, 
the  solids  are  separated  from  the   fluids   present  by  filtra- 
tion, the  solution  evaporated  to  dryness  and  the  residue  united 
with  the  solid  portion  ;  the  organic  matter  is  then  destroyed  by 
one  of  the  methods  previously  described.     In  the  special  case 
of  arsenic,  the  separation  of  the  poison  from  the  accompanying 
organic  materials  can  be  accomplished  by  a  process  not  yet 
mentioned  which  may  prove  to  be  of  service.     The  suspected 
substances  are  distilled  with  common  salt  and  concentrated 
sulphuric   acid.     By   this  operation  the  arsenic  is  converted 
into  a  volatile  chloride    which  distils  over.     The  poison  is 
isolated  by  treating  this  compound  with  water,  by  which  it  is 
decomposed   into   hydrochloric   and    arsenious   acids.       We 
must  give  preference,  however,  to  the  method  by  means  of 
chlorate  of  potassa  and  hydrochloric  acid. 

2.  The  solution  having  been  obtained  in  a  condition  suitable 
for  examination,  the  air  is  completely  expelled  from  the  ap- 
paratus by  allowing  the  gas  to  evolve  for  some  time,  and  the 
suspected  fluid  then  introduced  into  the  generating  flask.  Dan- 
ger  of   explosion  would  be  incurred  were  the   gas  ignited 
when  mixed  with  air.* 

*  The  effervescence  of  the  mixture  is  prevented  by  slowly  adding 
the  arsenical  solution  to  the  generating  flask.  In  order  to  avoid  loss  of 
arsenetted  hydrogen,  the  cold  dish  should  be  directly  applied  to  the  flame 
even  before  the  introduction  of  the  suspected  solution,  and  its  position 
changed  at  short  intervals,  so  as  to  allow  the  deposit  to  be  formed  on  dif- 
ferent parts. — Tram. 


DETECTION  OF  ARSENIC. 


27 


3.  It  is  indispensable,  in  applying  this  test,  to  have  a 
second  apparatus  in  which  only  the  reagents  necessary  to 
generate  hydrogen  are  placed :  in  this  way,  if  no  spots  are 
now  produced  by  the  use  of  the  second  apparatus,  it  is 
certain  that  those  obtained  when  the  first  apparatus  is  em- 
ployed do  not  originate  from  impurities  present  in  the  re- 
agents used. 

It  has  come  under  the  author's  observation,  however,  that  a 
sheet  of  zinc  sometimes  contains  arsenic  in  one  part  and  not  in 
another ;  in  fact,  the  shavings  of  this  metal,  as  purchased  for 
laboratory  use,  are  often  taken  from  lots  previously  collected, 
and  may  therefore  have  been  prepared  from  several  differ- 
ent sheets.  If  this  be  the  case,  it  is  supposable  that  the  zinc 
used  in  the  second  apparatus  may  be  free  from  arsenic, 
whereas  the  metal  with  which  the  suspected  solution  is 
brought  in  contact  may  contain  this  poison  ;  serious  danger 
would  then  exist  of  finding  indications  of  the  presence  of  arsenic 
in  materials  that  did  not  originally  contain  a  trace  of  the 
metal.  In  order  to  obviate  this  important  objection,  which 
might  possibly  place  a  human  life  in  jeopardy,  we  propose 
the  following  modifications :  Pure  mercury  is  distilled  and  its 
absolute  purity  established.  As  the  metal  is  a  fluid  and  is  there- 
fore homogeneous,  it  is  evident  if  one  portion  be  found 
pure,  the  entire  mass  is  so.  Sodium  is  then  fused  under  oil 
of  naphtha,  in  order  to  cause  the  complete  admixture  of  its 
particles,  and  the  purity  of  the  fused  metal  in  regard  to 
arsenic  tested.  An  amalgam  is  next  prepared  by  uniting 
the  mercury  and  sodium.  This  is  eminently  adapted  to  tox- 
icological  investigations:  in  order  to  generate  a  supply  of 
very  pure  hydrogen,  it  is  only  necessary  to  place  the  amalgam 
in  water  kept  slightly  acid  by  the  addition  of  a  few  drops 


28  LEGAL  CHEMISTRY. 

of  sulphuric  acid,  by  means  of  which  the  disengagement  of 
gas  is  rendered  more  energetic.* 

It  should  be  borne  in  mind  that  the  solution  introduced  into 
Marsh's  apparatus  must  not  contain  organic  substances,  and 
that,  in  case  their  destruction  has  been  accomplished  by  means 
of  nitric  acid  all  traces  of  this  compound  are  to  be  removed. 
The  sulphuric  acid  used  should  also  be  completely  freed  from 
nitrous  vapors.  According  to  M.  Blondeau,  nascent  hydrogen 
in  the  presence  of  nitrous  compounds  converts  the  acids 
of  arsenic  not  into  arsenetted  hydrogen  (As  H3),  but  into 
the  solid  arsenide  of  hydrogen  (As4  H2).  This  latter  com- 
pound, upon  which  pure  nascent  hydrogen  has  no  effect,  is 
transformed  into  gaseous  arsenetted  hydrogen  by  the  simulta- 
neous action  of  nascent  hydrogen  and  organic  substances. 
These  facts  are  of  the  greatest  importance,  for  they  might  pos- 
sibly cause  a  loss  of  arsenic  when  it  is  present,  as  well  as  deter- 
mine its  discovery  when  it  is  absent. 

The  first  case  is  supposable :  should  traces  of  nitric  acid 
remain  in  the  solution,  the  arsenic  would  be  transformed  into 
solid  arsenide  of  hydrogen  and  its  detection  rendered  impossi- 
ble. The  second  case  may  also  occur :  if  the  zinc  placed  in 
the  apparatus  contains  arsenic,  and  the  sulphuric  acid  used  con- 
tains nitrous  compounds,  the  evolved  gas  will  fail  to  exhibit 
any  evidence  of  the  presence  of  arsenic,  owing  to  the  forma- 
tion of  the  solid  arsenide  of  hydrogen.  Upon  adding  the  sus- 
pected solution,  which,  perchance,  may  still  contain  organic 
substances,  this  arsenide  is  converted  into  arsenetted  hydrogen, 
and  the  presence  of  arsenic  will  be  detected,  although  the  so- 
lution under  examination  was  originally  free  from  this  metal. 

*  Owing  to  the  impurities  often  occurring  in  zinc,  the  use  of  distilled 
magnesium  in  Marsh's  apparatus  has  also  been  suggested.     This  metal  is 


DETECTION  OF  ARSENIC.  29 


RASPAIL'S  METHOD. 

M.  Raspail  suggests  the  following  method  for  detecting 
arsenic  :  The  surface  of  a  brass  plate  is  rasped  by  filing.  In 
this  condition  the  plate  may  be  regarded  as  an  innumerable 
quantity  of  voltaic  elements,  formed  by  the  juxtaposition  of 
the  molecules  of  zinc  and  copper.  The  suspected  materials 
are  boiled  with  caustic  potassa,  the  solution  filtered,  a  drop  of 
the  filtrate  placed  upon  the  brass  plate,  and  a  drop  of  chlo- 
rine water  added.  If  the  plate  is  then  allowed  to  stand  for  a 
moment  and  the  substance  under  examination  contains  arse- 
nic, a  mirror-like  spot  is  soon  deposited  upon  its  surface.  In 
order  to  avoid  confounding  this  deposit  with  those  produced 
by  other  metals,  the  substitution  of  granulated  brass  for  the 
plate  is  in  some  cases  advisable.  The  granulated  metal  is 
dipped  successively  in  the  suspected  solution  and  in  chlorine 
water.  The  granules  retain  a  small  quantity  of  the  solutions 
and,  owing  to  the  action  of  the  chlorine  water,  become  covered 
with  metallic  spots,  if  arsenic  be  present.  They  are  then 
dried,  placed  in  a  tube  closed  at  one  end,  and  exposed  to  the 
heat  of  an  alcohol  lamp.  In  case  the  spots  are  arsenical, 
the  metal  volatilizes  and  condenses  in  a  ring  upon  the  cold 
part  of  the  tube,  which  is  submitted  to  the  tests  previously 
described. 

This  method  can  hardly  be  of  great  service,  inasmuch  as 

now  to  be  obtained  in  a  state  of  great  purity ;  it  is,  however,  sometimes 
contaminated  with  silicium,  which  body  likewise  gives  rise  to  a  metallic 
deposit,  but  one  that  is  readily  distinguished  from  arsenical  spots  by  its  in- 
solubility in  nitric  acid,  aqua  rcgia,  and  in  hypochlorite  of  soda.  The 
presence  of  magnesium  causes  the  precipitation  of  the  non-volatile  metals 
possibly  contained  in  the  fluid  tested  for  arsenic. — Trans. 


30  LEGAL  CHEMISTRY. 

it  extracts  the  poison  from  but  a  very  small  portion  of  the  solu- 
tion containing  it  :  we  have  not,  however,  personally  tested 
its  merits.* 

DETECTION  OF  A  >TI  M<».\  V  . 

Strictly  speaking  the  salts  of  antimony  are  more  thera- 
peutic than  poisonous  in  their  action.  In  fact  they  usually 
act  as  emetics  and,  under  certain  circumstances,  may  be  taken 
in  large  doses  without  incurring  serious  results.  There  are 
instances,  however,  in  which  their  action  is  truly  toxical,  and 
it  becomes  necessary  to  effect  their  detection  in  the  organs 

*  The  omission  in  the  text  of  Reinsch's  test  should  be  supplied.  This 
test  is  based  upon  the  fact  that  when  solutions  of  arsenious  acid  or  an 
arsenide  are  acidulated  with  hydrochloric  acid  and  boiled  with  metallic 
copper,  the  latter  becomes  covered  with  a  film  consisting  largely  of 
metallic  arsenic :  it  is  extensively  employed  in  chemico-legal  examinations. 
The  materials  to  be  examined  are  completely  disintegrated  by  boiling 
with  hydrochloric  acid,  and  the  fluid  filtered.  Some  pure  copper  gauze 
or  foil,  having  a  polished  surface,  is  then  immersed  in  the  boiling  solu- 
tion, and  notice  taken  of  the  formation  of  a  grey  deposit.  If  a  coating 
be  formed,  fresh  pieces  of  the  metal  are  added,  so  long  as  they  become 
affected.  The  copper  is  then  withdrawn  from  the  solution,  thoroughly 
washed  with  water,  and  dried,  either  by  means  of  the  water-bath  or  by 
pressing  between  bibulous  paper.  It  is  next  introduced  into  a  dry  tube, 
and  heated  over  a  spirit  lamp.  The  arsenic  present  volatilizes  and  is 
oxidized  to  arsenious  acid  which  forms  a  deposit,  consisting  of  octahedral 
crystals,  on  the  cold  part  of  the  tubes.  These  are  subsequently  tested 
by  means  of  the  reactions  distinctive  of  arsenious  acid.  It  need  hardly 
be  added  that  the  absolute  purity  of  both  the  hydrochloric  acid  and  of  the 
copper  is  to  be  carefully  established.  The  deposit  obtained  in  the  above 
operation  was  formerly  regarded  as  pure  arsenic,  but  it  has  been  proved 
to  be  an  alloy  consisting  of  32  per  cent,  arsenic,  and  68  per  cent,  copper. 
Reinsch's  test  possesses  the  advantage  of  requiring  but  little  time  for  its 
execution,  of  being  applicable  to  complex  organic  mixtures,  and  of  effect- 
ing the  detection  of  a  very  minute  trace  of  the  poison, — Trans. 


DETECTION  OF  ANTIMONY.  31 

of  a  body.  It  should  be  remarked  that  these  salts,  if  absorbed, 
remain  by  a  kind  of  predilection  in  the  liver  and  spleen.  A 
special  examination  of  these  organs  should  therefore  be  insti- 
tuted, particularly  if  the  fluids  of  the  alimentary  canal  are  not 
at  hand,  which  is  frequently  the  case  when  some  time  has 
elapsed  before  the  investigation  is  undertaken. 

The  remarks  made  in  the  preceding  article  concerning  the 
distinctive  properties  of  arsenic  and  antimony  need  not  be 
repeated  here.  The  search  for  antimony  is  likewise  executed 
by  aid  of  Marsh's  apparatus.  We  will  confine  ourselves  to  a 
description  of  a  modification  to  this  apparatus  proposed  by 
MM.  Flandin  and  Danger,  and  employed  in  the  separation  of 
antimony  and  arsenic,  when  a  mixture  of  these  metals  is  under 
examination.  Another  process,  by  means  of  which  we  arrive 
at  the  same  result  with  greater  certainty  and  by  the  use  of  a 
less  expensive  apparatus,  will  then  be  mentioned.  We  will, 
however,  first  indicate  the  preferable  method  of  destruction 
of  the  organic  substances. 

Were  the  decomposition  performed  by  means  of  sulphuric 
acid,  sulphate  of  antimony,  a  slightly  soluble  salt  and  one 
not  well  adapted  to  the  subsequent  treatment  with  nascent 
hydrogen,  would  be  formed.  In  order  to  obtain  the  metal  in  a 
soluble  state,  the  formation  of  a  double  tartrate  of  antimony 
and  soda  is  desirable.  This  may  be  accomplished  in  the 
following  manner: 

i.  A  cold  mixture  of  nitrate  of  soda,  sulphuric  acid,  and  the 
suspected  materials  is  prepared  in  the  proportion  of  25  grammes 
of  the  nitrate  to  39  grammes  of  the  acid,  and  100  grammes 
of  the  substance  under  examination.  This  mixture  is  heated 
and  evaporated  to  dryness,  and  the  decomposition  of  the  or- 
ganic matter  completed  in  the  usual  manner.  The  carbonaceous 
residue  obtained  is  pulverized,  and  then  boiled  with  a  solution 


32  LEGAL  CHEMISTRY. 

of  tarfaric  acid.  By  this  treatment  the  antimonate  of  soda 
present  is  converted  into  a  double  tartrate  of  antimony  and 
soda,  which  is  easily  soluble  in  water.  The  solution  is  filtered 
and  then  introduced  into  Marsh's  apparatus. 

2.  Another  method  consists  in  heating  the  substances 
under  examination  with  one  half  of  their  weight  of  hydrochloric 
acid  for  six  hours  on  a  sand-bath,  avoiding  boiling.  The 
temperature  is  then  increased  until  the  liquid  is  in  a  state  of 
ebullition,  and  15  to  20  grammes  of  chlorate  of  potassa,  for  every 
100  grammes  of  the  suspected  matter  taken,  added  in  successive 
portions,  so  that  a  quarter  of  an  hour  is  required  for  the  oper- 
ation. The  liquid  is  next  filtered,  and  the  resinous  matter 
remaining  on  the  filter  well  washed  with  distilled  water ;  the 
washings  being  added  to  the  principal  solution.  A  strip  of 
polished  tin  is  then  immersed  in  the  liquid  :  in  presence  of  a 
large  amount  of  antimony  the  tin  becomes  covered  with  a 
black  incrustation  :  if  but  a  minute  quantity  of  the  metal  is 
contained,  only  a  few  blackish  spots  are  perceptible.  After 
the  tin  has  remained  immersed  for  24  hours,  it  is  withdrawn 
and  placed  in  a  flask  together  with  an  amount  of  hydrochloric 
acid  sufficient  for  its  solution  in  the  cold.  If,  after  several 
hours,  blackish  particles  are  still  observed  floating  in  the 
liquid,  they  can  be  dissolved  in  a  few  drops  of  aqua  regia. 
The  solution  may  then  be  directly  introduced  into  Marsh's 
apparatus. 

APPARATUS    PROPOSED    BY   FLANDIN   AND   DANGER. 

This  apparatus  consists  of  a  wide  necked  jar  A  (Fig.  7)  for 
the  generation  of  the  gas,  the  mouth  of  which  is  closed  with 
a  cork  having  two  openings.  The  safety  tube  S,  which  is 
funnel-shaped  at  its  upper  extremity  and  has  its  lower  end 
drawn  out  to  a  point,  passes  through  one  of  these  apertures  : 


DETECTION  OF  ANTIMONY. 


33 


Fig.  7. 

the  other  opening  contains  the  small  delivery  tube  B,  open  at 
both  ends,  and  terminating  in  a  point  at  its  upper  extremity : 
it  is  also  provided  with  lateral  openings,  in  order  to  prevent 
the  solution  being  carried  up  to  the  flame.  The  second  part 
of  the  apparatus  is  the  condensor  C,  0.03  metre  in  diameter, 
and  0.25  metre  in  length.  This  terminates  at  its  lower  ex- 
tremity with  a  cone,  and  connects  at  the  side  with  the  tube  T, 
slanting  slightly  downwards.  In  the  interior  of  the  condenser, 
the  cooler  E  is  contained,  the  lower  end  of  which  is  nearly  in 
contact  with  the  sides  of  the  opening  O.  The  combustion  tube 
Z>,  o.oi  metre  in  diameter,  is  connected  by  means  of  a  cork 
with  the  tube  T ' ;  it  is  bent  at  right  angles,  and  encloses  the 
tube  jB,  in  such  a  manner  as  to  allow  the  evolved  gas  to  burn 
in  its  interior.  The  dish  J*"is  placed  beneath  the  opening  O. 

If    the  gas   which  burns  in  the  combustion  tube    contains 

->* 


34 


LEGAL  CHEMISTRY. 


arsenetted  hydrogen,  water  and  arsenious  acid  are  produced. 
A  portion  of  this  acid  is  retained  in  the  tube  Z>,  the  remainder 
is  carried  over,  with  the  aqueous  vapor,  into  C,  where  it  conden- 
ses, and  finally  falls  into  the  dish  f.  Both  portions  are  subse- 
quently examined  by  means  of  reactions  necessary  to  establish 
the  presence  of  the  acid.  If  the  ignited  gas  contains  antimo- 
netted  hydrogen,  water  and  an  intermediate  oxide  of  antimony 
are  formed.  The  latter  compound  is  entirely  retained  in  the 
tube  D  separated  from  the  greater  part  of  the  arsenious  acid, 
if  this  body  be  present,  and  can  be  brought  into  solution  by 
means  of  a  mixture  of  hydrochloric  and  tartaric  acids.  A  fluid 
is  then  obtained  which  can  be  introduced  into  Marsh's  appar- 
atus, or  otherwise  examined  for  antimony. 

NAQUET'S  APPARATUS. 

Although  the  separation  of  arsenic  from  antimony  is  the 
chief  object  in  making  use  of  the  apparatus  proposed  by 
Flandin  and  Danger,  it  is  evident  that  this  result  is  not  fully 
accomplished,  since  a  small  portion  of  arsenious  acid  remains 


Fig- 3. 


DETECTION  OF  ANTIMONY.  35 

in  the  tube  D  (Fig.  7),  together  with  the  intermediate  oxide  of 
antimony.  The  following  method  secures  the  complete  separ- 
ation of  these  metals  :  An  amalgam  of  sodium  and  mercury  is 
introduced  into  the  flask  A,  (Fig.  8),  which  is  provided  with 
two  openings.  The  tube  B,  terminating  in  a  funnel  at  its  upper 
extremity,  passes  through  one  of  these  orifices.  The  other 
aperture  contains  a  cork  enclosing  the  small  tube  C,  which  is 
bent  at  a  right  angle  and  communicates,  by  means  of  a  cork, 
with  the  larger  tube  D  filled  with  cotton  or  asbestus.  A  set 
of  Liebig's  bulbs,  E,  containing  a  solution  of  nitrate  of  silver, 
is  attached  to  the  other  extremity  of  this  tube.  The  apparatus 
being  mounted,  the  solution  under  examination  is  slightly 
acidulated  and  introduced  by  means  of  the  tube  B  into  the 
flask  A :  the  disengagement  of  gas  begins  immediately.  If 
arsenic  and  antimony  are  contained  in  the  solution,  arsenetted 
hydrogen  and  antimonetted  hydrogen  are  evolved.  Both 
gases  are  decomposed  in  passing  through  the  solution  of  nitrate 
of  silver  contained  in  the  Liebig  bulbs  :  the  arsenetted  hydro- 
gen causes  a  precipitation  of  metallic  silver,  all  the  arsenic  re- 
maining in  solution  as  arsenious  acid ;  the  antimonetted 
hydrogen  is  decomposed  into  insoluble  antimonate  of  silver. 
After  the  operation  has  continued  for  several  hours,  the  appar- 
atus is  taken  apart,  the  nitrate  of  silver  solution  thrown  on  a 
filter,  and  the  precipitate  thoroughly  washed.  An  excess  of 
hydrochloric  acid  is  then  added  to  the  filtrate,  and  the  preci- 
pitate formed  separated  from  the  solution  by  filtration,  and 
well  washed.  The  wash-water  is  added  to  the  solution,  and 
the  whole  then  examined  for  arsenic  by  means  of  Marsh's 
test. 

The  precipitate  formed  in  the  nitrate  of  silver  solution, 
which  contains  antimonate  of  silver,  is  well  dried,  mixed  with 
a  mixture  of  carbonate  and  nitrate  of  soda,  and  calcined  in  a 


36  LEGAL  CHEMISTRY. 

porcelain  crucible  for  about  three-quarters  of  an  hour.  The 
crucible  is  then  removed  from  the  fire,  and  the  cooled  mass 
treated  with  hydrochloric  acid  until  a  drop  of  the  filtered 
fluid  ceases  to  give  a  residue  when  evaporated  upon  a  watch- 
glass  to  dryness.  A  current  of  sulphurous  acid  is  now  con- 
ducted through  the  filtered  solution  until  the  odor  of  this  gas 
remains  persistent.  The  excess  of  acid  is  then  removed  by 
boiling,  and  the  solution  placed  in  Marsh's  apparatus  and 
tested  for  antimony. 

DETECTION  OF  MERCURV. 

If  a  mercurial  salt  exists  in  a  considerable  quantity  in  the 
substances  extracted  from  the  alimentary  canal,  or  ejected 
either  by  stools  or  vomiting,  it  can  be  isolated  by  treating 
these  materials  with  water,  filtering  the  liquid,  and  evaporating 
the  filtrate  to  dryness.  The  residual  mass  is  taken  up  with 
alcohol,  and  the  solution  again  filtered  and  evaporated. 
Upon  dissolving  the  residue  obtained  by  this  operation  in 
ether  and  filtering  and  evaporating  the  solution,  a  residue  is 
obtained  which  when  dissolved  in  water  forms  a  fluid  where- 
in the  presence  of  mercury  can  be  detected  by  means  of  the 
ordinary  tests. 

When,  however,  only  a  minute  quantity  of  mercury  is 
present,  and  this  has  been  absorbed,  its  detection  is  more 
difficult.  It  will  be  necessary  under  these  circumstances  to 
make  use  of  either  Smithson's  pile  or  Flandin  and  Danger's 
apparatus. 

SMITHSON'S  PILE. 

Smithson's  pile  consists  of  a  small  plate  of  copper  around 
which  a  piece  of  thin  gold  foil  is  wrapped.  This  is  immersed 
in  the  solution  to  be  tested  for  mercury,  which  has  previously 


DETECTION  OF  MERCURY.  37 

been  slightly  acidulated :  if  mercury  be  present,  the  plate 
acquires  a  white  color  which  disappears  upon  exposure  to  the 
flame  of  a  spirit-lamp.  A  similar  reaction  occurs  in  presence 
of  tin,  as  this  metal  would  likewise  be  deposited  upon  the 
plate,  and,  upon  heating,  would  penetrate  the  metal  and  re- 
store to  it  its  natural  color.  The  danger  of  mistake  arising 
from  this  fact  is  obviated  by  introducing  the  copper  plate  in- 
to a  tube  closed  at  one  end  and  bent  at  a  right  angle.  The 
open  extremity  of  the  tube  is  drawn  out  to  a  fine  point  and 
immersed  in  water  contained  in  a  second  tube  also  closed  at 
one  end.  Upon  heating  the  plate  in  the  flame  of  an  alcohol 
lamp,  the  white  color  disappears  if  produced  by  mercury,  and 
at  the  same  time  this  metal  condenses  in  the  narrow  extremity 
of  the  tube.  The  metallic  globules  formed  can  be  recognized 
either  by  the  naked  eye  or  with  the  aid  of  a  lens,  or  by  rub- 
bing them  with  a  piece  of  gold  foil  when  the  latter  will  ac- 
quire a  white  coating. 

When  Smithson's  pile  is  employed,  the  organic  substances 
are  most  advantageously  decomposed  by  means  of  chlorine. 
It  is  advisable  to  operate  with  as  small  a  quantity  of  fluid  as 
possible,  for,  owing  to  the  volatility  of  bichloride  of  mercury, 
a  portion  of  this  salt  may  be  lost  by  the  evaporation  of 
aqueous,  alcoholic,  and  even  etherial  solutions,  and  the  detec- 
tion of  minute  quantities  rendered  impossible. 

APPARATUS    PROPOSED    BY   FLANDIN   AND   DANGER. 

This  apparatus  consists  of  a  stand  S,  (Fig.  9)  supporting  a 
balloon  A,  which  serves  as  the  reservoir  of  the  suspected  solu- 
tion, and  a  funnel  £,  into  which  the  neck  of  the  balloon  is 
dipped.  The  funnel  B  is  bent  at  a  right  angle  and  is  drawn  out 
at  its  lower  end  under  which  the  dish  C  is  placed  for  the 
reception  of  the  escaping  fluids.  A  fine  wire  of  pure  gold, 


LEGAL  CHEMISTRY. 


forming  the  negative  electrode  of  a  Bunsen's  battery,  passes 
through  the  lower  extremity  of  the 
funnel.  The  end  of  this  wire  nearly 
comes  in  contact  with  a  second  wire,  in- 
serted in  the  upper  part  of  the  funnel, 
and  connected  with  the  positive  pole  of 
the  battery.  If  the  balloon  filled  with 
the  solution  is  inverted  and  immersed 
in  the  funnel  B,  its  neck  will  be  sub- 
merged at  first  ;  soon,  however,  it  be- 
comes uncovered,  owing  to  the  depres- 
sion of  the  level  of  the  fluid  caused  by  the 
escape  of  the  latter  through  the  tapering 
extremity  of  the  funnel :  a  bubble  of  air 
then  passes  in  the  balloon  and  expels  a 
Fig.  9.  drop  of  the  solution.  This  process 

is  repeated  at  short  intervals,  causing  a  continuous  flow 
of  the  fluid,  the  rapidity  of  which  is  easily  regulated  by 
elevating  or  lowering  the  balloon,  thus  raising  or  depressing 
the  level  of  the  liquid.  The  apparatus  having  been  mounted 
in  this  manner  and  the  battery  set  in  action,  the  disengage- 
ment of  gas  commences.  Should  mercury  be  contained  in  the 
solution  under  examination,  this  metal  will  be  deposited  upon 
the  negative  wire.  When  the  operation  is  completed  this 
wire  is  detached  from  the  apparatus,  washed  with  ether,  and 
dried.  It  is  then  introduced  into  a  small  tube  provided  with 
a  bulb,  and  the  mercury  volatilized  by  means  of  the  blow  pipe 
flame:  the  metal  condenses  in  the  bulb  of  the  tube  in 
globules  which  are  readily  recognized.  They  can  also  be  dis- 
solved in  nitric  acid,  and  the  presence  of  a  mercurial  salt  in 
the  solution  confirmed  by  further  tests, 


DETECTION  OF  PHOSPHORUS. 


39 


The  solution  to  be  examined  in  the  preceding  apparatus, 
is  prepared  as  follows  : 

The  suspected  organic  matter  is  treated  with  cold  sulphuric 
acid  of  66°  B.  until  liquefied,  and  hypochlorite  of  lime,  and  dis- 
tilled water  then  added  :  if  necessary,  the  evolution  of  chlorine 
can  be  accelerated  by  a  further  addition  of  sulphuric  acid. 
As  soon  as  the  liquid  becomes  clear,  it  is  filtered,  concentra- 
ted and  examined  as  described  above.  The  solution  con- 
tains the  mercury  in  the  state  of  bichloride,  a  salt  soluble  in 
water  and  well  adapted  to  the  above  test. 

The  substitution  of  a  large  balloon,  having  a  capacity  of 
about  2  litres,  in  place  of  the  small  vessel  of  Flandin  and 
Danger's  apparatus,  is  to  be  recommended  as  doing  away  with 
the  necessity  of  evaporation  ;  an  operation  which  invariably 
causes  a  loss  of  substance.  The  apparatus,  modified  in  this 
manner,  is  the  most  delicate  in  use  for  the  detection  of 
mercury. 

DETECTION  OF  PHOSPHORUS. 

ORFILA'S  METHOD. 

The  solid  substances  found  in  the  alimentary  canal  are 
mechanically  separated  from  the  fluids  present  by  means  of  a 
linen  cloth.  They  are  then  examined  by  aid  of  a  magnify- 
ing glass,  and  any  fragments  of  phosphorus  found  separated 
and  preserved  under  water.  If  none  are  discovered,  the 
presence  of  phosphorescent  vapors  may  possibly  be  detected 
by  examining  the  materials  in  the  dark.  In  any  case,  a  por- 
tion of  the  suspected  materials  should  be  treated  with  nitrate 
of  silver:  in  presence  of 'phosphorus  the  materials  acquire, 
first,  a  reddish-brown,  then,  a  black  color.  The  remaining 


40  LEGAL  CHEMISTRY. 

portion  is  spread  upon  a  shovel  and  heated :  a  white  flame, 
burning  at  various  points  of  the  mass,  and  originating  from 
the  combustion  of  phosphorus,  is  observed,  if  this  body  be 
contained  in  the  substances  under  examination.  This  method 
is  evidently  far  from  perfect. 

MISTCHERLICH'S  METHOD. 

Mistcherlich's  method  is  based  upon  the  luminosity  of  the 
vapors  of  phosphorus.  The  suspected  materials  are  moistened 
with  dilute  sulphuric  acid,  and  heated,  in  a  flask  communicating 
with  a  glass  worm  which  passes  through  a  glass  cooler  into  a 
receiver.  If  the  apparatus  is  placed  in  the  dark,  and  the 
materials  contain  phosphorus,  luminous  vapors  will  be  observed 
in  the  flask  and  receiver.  When  the  quantity  of  the  poison 
piesent  is  considerable,  the  phosphorous  acid  formed  can  be 
collected  and  its  properties  tested. 

DUSART'S  METHOD,  AS  MODIFIED  BY  BLONDLOT. 

Dusart's  process  takes  advantage  of  the  facility  with  which 
hydrogen  combines  with  phosphorus.  The  substances  under 
examination  are  placed  between  two  asbestus  stoppers  in  a 
tube,  one  end  of  which  tapers  to  a  point,  and  a  current  of 
pure  hydrogen  conducted  over  them.  In  presence  of  phos- 
phorus the  evolved  gas  will  burn  with  a  green  flame,  and,  upon 
bringing  this  in  contact  with  a  porcelain  plate,  red  spots  will 
be  deposited  upon  the  latter.  Blondlot  prefers  to  introduce 
the  suspected  materials  into  the  flask  in  which  the  hydrogen 
is  generated.  He  employs  the  apparatus  represented  in  Fig. 
10  :  a  is  a  flask  for  evolving  hydrogen  ;  b  is  a  U  tube,  filled 
with  fragments  of  pumice  stone  which  are  saturated  with  a 
concentrated  solution  of  potassa  ;  c  is  a  Mohr  clamp ;  d  a 
screw-clamp ;  e  a  platinum  jet.  This  jet  is  necessary  in 


DETECTION  OF  PHOSPHORUS. 


order  to  avoid  a  yellow  coloration  of  the  flame  by  the  soda 
contained  in  the  glass.  Pure  hydrogen  is  at  first  evolved,  in 
order  to  ascertain  that  the  flame  is  colorless  and  red  spots 
are  not  produced  when  it  is  intersected  by  a  cold  plate.  The 
purity  of  the  reagents  used  having  thus  been  confirmed,  the 


42  LEGAL  CHEMISTRY. 

clamp  d  is  closed  until  the  acid  is  forced  back  intof;  and  the 
materials  to  be  examined  are  then  added  to  the  fluid.  Upon 
opening  the  clamp  the  liquid  passes  from/"  into  a,  and  the 
evolution  of  gas  recommences.  The  gas  is  then  ignited  :  the 
flame  possesses  the  characteristic  properties  mentioned  above, 
if  the  suspected  substances  contain  phosphorus. 

METHOD   PROPOSED   BY   FRESENIUS   AND   NEUBAUER. 

According  to  this  method,  the  materials  are  brought  into  a 
flask  provided  with  a  doubly-perforated  stopper,  and  water, 
acidulated  with  sulphuric  acid,  added.  The  flask  is  then 
heated  over  a  water-bath,  and  a  current  of  carbonic  acid 
conducted  through  the  mixture  for  at  least  two  hours.  The 
gas,  on  leaving  the  flask,  passes  into  a  solution  of  nitrate  of 
silver.  Should  no  precipitate  form  in  this  solution,  the  absence 
of  free  phosphorus  is  established,  for,  were  this  body  present, 
a  portion  would  be  volatilized,  and  a  black  precipitate,  consist- 
ing of  phosphide  of  silver,  together  with  phosphoric  acid, 
produced.  The  formation  of  a  black  precipitate  is,  however, 
not  necessarily  a  proof  of  the  presence  of  phosphorus.  In 
order  to  conclusively  determine  the  character  of  the  precipi- 
tate, it  is  collected  on  a  filter  and  examined  by  the  method  of 
Dusart  and  Blondlot. 

This  process  has  given  result  in  cases  where  none  were 
obtained  by  Mistcherlich's  method.  It  possesses,  moreover, 
an  advantage  over  the  latter  process,  in  not  being  influenced 
by  the  presence  of  foreign  bodies ;  whereas,  in  Mistcherlich's 
method,  some  time  must  elapse  before  the  luminosity  of  the 
vapors  becomes  apparent  if  ether  or  alcohol  is  contained  in 
the  solutions,  and  this  phenomenon  totally  fails  to  appear  in 
presence  of  oil  of  turpentine. 


DETECTION  OF  PHOSPHORUS.  43 

DETECTION   OF   PHOSPHORUS    BY   THE    USE   OF    BISULPHIDE   OF 
CARBON. 

In  a  report  read  before  the  Academy  of  Sciences  in  1856, 
presented  by  an  examining  commission,  of  which  MM. 
Dumas,  Pelouze  and  Claude  Bernard  were  the  reporters,  the 
following  results  were  contained :  Phosphorus  may  remain,  in 
the  free  state,  in  the  organs  fifteen  days  after  death,  and  even 
then  its  isolation  can  easily  be  accomplished.  For  this  pur- 
pose the  stomach  or  intestines,  and  the  articles  of  food  con- 
tained therein,  are  cut  into  pieces  and  treated  with  bisulphide 
of  carbon.  Upon  filtering  the  liquid,  a  solution  is  obtained 
containing  all  the  phosphorus  present,  which  exhibits  the 
following  properties :  ist,  When  ignited,  it  burns  with  a  very 
luminous  flame;  2nd,  if  allowed  to  spontaneously  evaporate 
(the  combustion  of  the  phosphorus  being  prevented  by  the 
organic  matter  present  \Naquet\)  an  inflammable  residue  is 
obtained,  which,  if  dissolved  in  boiling  monohydrated  nitric 
acid,  gives  a  solution  that,  after  saturation  with  ammonia,  pro- 
duces a  precipitate  soluble  in  acids  in  solutions  of  barium 
salts.  If  the  solution  is  mixed  with  perchloride  of  iron,  and 
the  sesquioxide  of  this  metal  subsequently  eliminated  by  the 
addition  of  ammonia,  it  no  longer  causes  a  precipitation  in 
barium  solutions.  The  fluid  acquires  a  yellow  coloration  when 
boiled  with  a  solution  of  molybdate  of  ammonia. 

According  to  our  personal  experience,  the  apparatus  em- 
ployed by  Flandin  and  Danger  for  the  detection  of  arsenic, 
can  also  be  made  use  of  in  the  examination  of  the  bisulphide 
of  carbon  solution.  To  this  end,  the  fluid  supposed  to  con- 
tain phosphorus  is  mixed  with  perfectly  pure  alcohol,  and  the 
mixture  placed  in  a  small  spirit-lamp  provided  with  a  very 
loose  asbestus  wick.  The  lamp  is  then  ignited  and  the  flame 
introduced  in  the  combustion  tube  D  (Fig.  n). 


44 


LEGAL  CHEMISTRY. 


Fig.  II. 

By  the  combustion  of  the  mixture,  sulphurous,  carbonic, 
phosphorous  acids  and  water  are  formed.  The  water  condenses 
in  c,  and,  falling  into  the  dish  F,  carries  with  it  the  sulphurous 
and  phosphorous  acids.  The  acid  liquid  collected  in  this  way 
is  evaporated-  to  dryness,  some  nitric  acid  added,  and  the 
solution  again  evaporated.  The  remaining  mass  is  then  dis- 
solved in  water  to  which  some  ammonia  is  added,  and  the 
solution  tested  for  phosphoric  acid.  This  method  is  an  ad- 
vantageous one  as  the  phosphoric  acid  formed  must  originate 
from  phosphorus  in  the  free  state,  and  not  from  any  phosphates 
which,  owing  to  the  presence  of  organic  matter,  might  be  con- 
tained in  the  bisulphide  of  carbon  solution.  It  would,  how- 
ever, lead  the  analyst  into  error  if  the  person,  supposed  to  have 
been  poisoned  had  eaten  cerebral  substances  or  eggs  previous 
to  death,  as  these  contain  glycero-phosphoric  acid ;  it  is  there- 


DETECTION  OF  PHOSPHOROUS  ACID. 


45 


fore  advisable  to  compare  the  results  given  by  this  process  with 
those  obtained  by  the  use  of  other  methods. 

DETECTION   OF   PHOSPHOROUS   ACID. 

Provided  free  phosphorus  has  not  been  detected,  it  is 
necessary  to  search  for  phosphorous  acid.  To  this  end,  the 
residue  remaining  in  the  flask,  in  either  Mistcherlich's  or 
Fresenius  and  Neubauer's  method,  is  introduced  into  the 
apparatus  of  Dusard  and  Blondlot.  If  the  phosphorus  re- 
action appears,  it  is  sufficient ;  otherwise,  its  production  may 
have  been  hindered  by  the  presence  of  organic  matter.  In 
case,  therefore,  the  flame  is  colorless,  the  evolved  gas  is  con- 
ducted into  a  neutral  solution  of  nitrate  of  silver.  If  the 
materials  contain  phosphorous  acid,  a  precipitate  of  phosphide 
of  silver  is  formed  which  should  be  collected  and  washed. 
The  precipitate,  which  is  now  free  from  organic  matter,  is  then 
examined  for  phosphorous  acid  by  means  of  the  apparatus  of 
Dusard  and  Blondlot. 

ESTIMATION    OF    PHOSPHORUS. 

The  best  process  for  determining  quantitatively  the  amount 
of  phosphorus  present  is  the  one  recommended  by  Fresenius 
and  Neubauer.  The  gaseous  current  is  continued  until  a 
fresh  nitrate  of  silver  solution  is  no  longer  precipitated.  The 
solution  is  filtered,  the  precipitate  washed  and  then  dissolved 
in  nitric  acid.  The  silver  is  next  precipitated  by  addition  of 
hydrochloric  acid,  the  fluid  again  filtered,  and  the  precipitate 
well  washed.  The  washings  are  added  to  the  filtrate,  and  the 
liquid  concentrated  in  a  porcelain  capsule.  A  solution  of 
sulphate  of  magnesia,  containing  ammonia,  is  next  added  to 
the  fluid,  and  the  phosphoric  acid  determined  as  pyrophosphate 


46  LEGAL  CHEMISTRY. 

of  magnesia  :  the  precipitate  formed,  is  washed,  heated  to  red- 
ness, in  order  to  convert  it  into  the  pyrophosphate,  and  then 
weighed. 

DETECTION  OF  ACIDS. 

The  search  for  acids  is  to  be  instituted  exclusively  in  the 
alimentary  canal  and  its  contents.  Were  acids  contained  in 
the  other  organs,  their  presence  would  be  due  to  the  blood  in 
which  they  had  previously  been  absorbed,  and,  as  in  this  case 
they  would  be  partially  neutralized  by  the  bases  contained 
in  the  blood,  a  conclusive  decision  in  regard  to  their  original 
existence  in  the  suspected  materials  would  be  impossible,  the 
salts  of  the  acids  usually  searched  for  being  normal  constitu- 
ents of  the  blood.  In  order  to  detect  the  presence  of  acids, 
the  alimentary  canal  and  contents  are  first  boiled  with  water 
which  is  renewed  until  the  solution  ceases  to  exhibit  an  acid 
reaction  when  tested  with  litmus  paper.  The  fluid  is  then 
filtered,  alcohol  added  to  the  filtrate,  in  order  to  precipitate 
organic  substances,  the  liquid  again  filtered,  and  the  solution 
tested  separately  for  the  various  acids  as  directed  below. 

.    HYDROCHLORIC   ACID. 

The  solution  is  placed  in  a  retort  provided  with  a  receiver 
and  distilled  until  the  residual  fluid  assumes  a  pasty  consist- 
ence :  the  operation  is  then  discontinued.  If  hydrochloric 
acid  be  present  in  the  materials  under  examination,  the  dis- 
tillate will  have  an  acid  reaction,  and,  upon  addition  of  solu- 
tion of  nitrate  of  silver,  a  white  precipitate,  which  is  easily 
soluble  in  ammonia  but  insoluble  in  nitric  acid  and  in  short 
possesses  all  the  properties  of  chloride  of  silver,  will  be 
formed. 


DETECTION  OF  ACIDS.  47 

NITRIC   ACID. 

The  distillate,  obtained  as  in  the  preceding  process,  is 
neutralized  by  the  addition  of  potassa  or  soda,  and  evaporated 
to  dryness.  The  residue  is  mixed  with  copper  filings,  and 
introduced  into  a  glass  tube  closed  at  one  end  and  provided 
at  the  other  with  a  cork  through  which  a  delivery-tube  passes. 
Sulphuric  acid  is  then  added  to  the  mixture,  the  cork  inserted, 
the  tube  heated,  and  the  evolved  vapors  conducted  into  a  so- 
lution of  protosulphate  of  iron.  The  latter  solution  acquires 
a  brown  coloration  which,  upon  addition  of  sulphuric  acid, 
changes  to  a  violet,  if  nitric  acid  be  present.  Upon  conducting 
the  disengaged  gas  into  a  solution  of  narcotine,  the  latter 
acquires  a  beautiful  red  color. 

Another  portion  of  the  residue  should  deflagrate  when 
saturated  with  an  alkali  and  projected  upon  live  coals. 

SULPHURIC    ACID. 

In  order  to  detect  this  acid,  the  solution  obtained  by  treat- 
ing the  organs  with  water  is  not  distilled  but  is  concentrated 
to  one-sixth  of  its  original  volume,  and  then  agitated  with 
ether  for  about  ten  minutes.  By  this  treatment  the  ether 
takes  up  the  free  sulphuric  acid,  but  not  the  acid  sulphates 
present.  After  ten  minutes  contact,  the  ether  is  decanted 
and  allowed  to  spontaneously  evaporate.  Upon  treating  the 
residue,  which  contains  the  free  sulphuric  acid  and  fatty  sub- 
stances, with  water,  a  solution  containing  only  the  sulphuric 
acid  is  obtained.  Nitrate  of  baryta  is  then  added  to  a  portion 
of  the  fluid  :  in  presence  of  sulphuric  acid,  a  white  precipitate, 
insoluble  in  acids,  is  produced.  If  this  is  heated  on  charcoal  be- 
fore the  blow-pipe,  a  mass  is  formed,  which,  when  moistened 


48  LEGAL  CHEMISTRY. 

with  hydrochloric  acid  and  placed  upon  a  clean  silver  coin, 
produces  a  black  spot  on  the  metal.  Another  portion  of  the 
solution  is  mixed  with  copper  and  the  mixture  evaporated  in  a 
tube  closed  at  one  end  :  sulphurous  acid  is  evolved  towards  the 
end  of  the  operation.  This  gas  is  detected  by  allowing  it  to 
pass  over  paper  saturated  with  a  mixture  of  iodic  acid  and 
starch  ;  a  blue  coloration  is  produced  which,  owing  to  the  trans- 
formation of  the  iodine  set  free  into  hydriodic  acid,  subsequent- 
ly disappears.  (We  have  never  been  able  to  effect  the  disengage- 
ment of  sulphurous  acid  spoken  of  above  when  an  exceeding- 
ly dilute  sulphuric  acid  was  used,  even  upon  evaporating 
the  mixture  to  dryness,  notwithstanding  Orfila's  statement 
that  the  reaction  occurs  very  readily.) 

PHOSPHORIC  ACID. 

The  aqueous  solution  is  evaporated  to  dryness,  the  residue 
taken  up  with  alcohol  of  44°  B.,  the  fluid  again  evaporated,  and 
the  second  residue  dissolved  in  water.  Upon  adding  acetate 
of  lead  to  the  solution,  a  white  precipitate  is  produced  if  phos- 
phoric acid  be  present.  The  precipitate  is  washed,  sus- 
pended in  water  and  a  current  of  sulphuretted  hydrogen  passed 
through  the  mixture.  If  the  fluid  is  then  filtered,  and  the  ex- 
cess of  sulphuretted  hydrogen  expelled  from  the  filtrate  by 
boiling,  a  liquid  possessing  the  distinctive  propertiss  of  a  solu- 
tion of  phosphoric  acid  will  be  obtained.  This  should  then  be 
submitted  to  the  following  tests  :  Some  pulverized  charcoal  is 
added  to  a  portion  of  the  solution,  the  mixture  evaporated  to 
dryness,  and  the  residue  obtained  introduced  into  a  Hessian 
crucible  heated  to  redness  :  in  presence  of  a  considerable 
amount  of  the  acid,  free  phosphorous  is  liberated  and  burns 
with  a  bright  flame  in  the  upper  part  of  the  crucible.  In 


DETECTION  OF  ACIDS.  49 

case  this  reaction  fails  to  occur,  other  portions  of  the  fluid  are 
treated  with  a  solution  of  a  baryta  salt,  which  causes  a  white 
precipitate,  soluble  in  nitric  acid  ;  with  an  ammoniated  solution 
of  sulphate  of  magnesia,  which  throws  down  a  crystalline 
white  precipitate ;  and  by  boiling  with  molybdate  of  ammonia, 
acidulated  with  nitric  acid,  which  produces  a  yellow  pre- 
cipitation, or  at  least  a  yellow  coloration  of  the  solution. 

OXALIC  ACID. 

The  solution  is  subjected  to  the  same  treatment  as  in  the 
search  for  phosphoric  acid,  with  the  exception  that,  instead  of 
adding  acetate  of  lead  to  the  fluid  obtained  by  taking  up  the 
residue  left  from  the  alcohol  with  water,  it  is  divided  into  two 
portions  which  are  examined  separately.  A  solution  of  a  lime 
salt  is  added  to  one  portion :  if  oxalic  acid  be  present,  a  pre- 
cipitate, which  is  insoluble  in  acetic  acid  or  in  chloride  of 
ammonium,  and  effervesces  when  slightly  calcined  and  treated 
with  hydrochloric  acid,  is  formed.  Nitrate  of  silver  is  added 
to  the  remaining  portion  of  the  solution  :  the  formation  of  a 
precipitate,  which  detonates  when  dried  and  heated  in  a  glass 
tube  closed  at  one  end,  is  further  evidence  of  the  presence 
of  the  acid. 

ACETIC  ACID. 

The  solution  obtained  by  treating  the  alimentary  canal  with 
water  is  distilled,  as  in  testing  for  nitric  and  hydrochloric  acids, 
and  the  following  properties  verified  in  the  distillate  :  ist.  It 
has  an  acid  reaction,  and  possesses  the  odor  of  vinegar  ;  2nd, 
unless  previously  neutralized  with  a  base,  it  fails  to  redden  the 
per-salts  of  iron;  3rd,  if  the  distillate  is  added  to  a  solution  of 

3 


So  LEGAL  CHEMISTRY. 

the  per-salts  mentioned  and  sulphuretted  hydrogen  conducted 
through  the  fluid,  a  black  precipitate  is  formed ;  4th,  upon 
boiling  the  still  acid  fluid  with  a  small  quantity  of  starch,  the 
property  of  the  latter  to  become  colored  in  presence  of  free  iodine 
is  not  changed  ;  5th,  if  heated  with  an  excess  of  litharge,  a 
basic  salt  which  restores  the  blue  color  to  reddened  litmus 
paper  is  produced. 

HYDROCYANIC   ACID. 

The  detection  of  hydrocyanic  acid  requires  special  precau- 
tions. The  substances  to  be  examined  are  mixed  with  water, 
if  solids  are  present,  and  introduced  into  a  retort  provided 
with  a  delivery-tube  which  dips  in  a  solution  of  nitrate  of  sil- 
ver. The  retort  is  then  heated  over  a  water-bath.  If  the 
evolved  vapors  produce  a  precipitate  in  the  silver  solution, 
the  heating  is  continued  until  a  fresh  portion  of  the  latter  is  no 
longer  affected.  The  operation  is  now  interrupted,  hydro- 
chloric acid  added  to  the  retort,  and  heat  again  applied 
Should  a  second  precipitation  of  cyanide  of  silver  occur,  the 
presence  of  a  cyanide  in  the  suspected  materials  is  indicated ; 
whereas  the  formation  of  a  precipitate  by  the  simple  action  of 
heat  would  point  to  the  presence  of  free  hydrocyanic  acid  or 
cyanide  of  ammonium.*  In  case  the  latter  compound  is  pres- 
ent, ammonia  will  be  contained  in  the  distillate. 

In  order  to  identify  the  cyanogen,  a  portion  of  the  precipitate 
is  collected  upon  a  small  filter,  washed,  dried,  and  then  allowed 
to  fall  into  a  rather  long  tube,  closed  at  one  end,  in  the  bottom 

*  Ferrocyanides  and  ferricyanides — non-poisonous  compounds — likewise, 
evolve  hydrocyanic  acid  when  distilled  witlva  strong  acid.  Their  presence 
is  indicated  by  stirring  a  small  portion  of  the  materials  with  water,  filtering 
the  fluid,  acidulating  the  filtrate  with  hydrochloric  acid,  and  testing  two  por- 
tions :  one  with  sesquichloride  of  iron,  the  other  with  protosulphate  of  iron. 
If  either  of  the  above  salts  be  present,  a  blue  precipitate  is  produced. — Trans. 


DE  TECTION  OF  A  CIDS.  5 1 

of  which  some  iodine  has  previously  been  placed.  A  column  of 
carbonate  of  soda  is  then  introduced  above  the  precipitate  for 
the  purpose  of  retaining  the  excess  of  iodine  probably  taken. 
Upon  heating  the  lower  end  of  the  tube,  white  fumes  of  iodide 
of  cyanogen,  which  condense  in  needles  upon  the  cold  portion 
of  the  tube,  are  produced.  These  are  easily  recognized  by  aid 
of  a  magnifying  glass.  They  are  colorless  and  are  readily  vol- 
atilized by  heat.  Some  ammonia  is  next  added  to  a  solution 
of  protosulphate  of  iron,  the  precipitate  formed  thoroughly 
washed,  and  exposed  to  the  air  until  it  acquires  a  greenish  hue. 
The  iodide  of  cyanogen  is  then  withdrawn  from  the  tube  and 
mixed  with  potassa-lye  and  the  precipitate  mentioned  above. 
The  mixture  is  evaporated  to  dryness,  the  residue  obtained 
treated  with  water  and  the  filtered  solution  then  acidulated 
with  hydrochloric  acid.  If  a  solution  of  a  per-salt  of  iron  is  now 
added  to  the  fluid,  a  blue  precipitate  is  formed.  The  addition 
of  salts  of  copper  produces  a  reddish  precipitation. 

The  remainder  of  the  precipitate  formed  in  the  nitrate  of 
silver  solution  is  heated  with  sulphur  and  then  boiled  with  an 
aqueous  solution  of  chloride  of  sodium :  if  cyanogen  is  con- 
tained in  the  precipitate,  a  solution  of  sulphocyanate  of  soda 
will  be  formed,  and  upon  adding  sesquichloride  of  iron  an 
intense  red  coloration  produced. 

It  is  evident  that  the  presence  of  another  acid  in  the  solu- 
tion examined  for  hydrocyanic  acid  would  render  the  detection 
of  cyanides  impossible,  but  in  all  cases  hydrocyanic  acid  can 
be  separated  without  arriving  at  a  decision  in  regard  to  its 
original  state  of  combination.  Nitric,  hydrochloric,  and  several 
other  acids  would  not  be  distilled  at  the  temperature  of  the 
water-bath  ;  an  examination  for  these  by  the  methods  already 
described  can  therefore  be  instituted  simultaneously  with  the 
search  for  hydrocyanic  acid. 


5 2  LEGAL  CHEMISTRY. 

DETECTION  OF  AI,K AI-IKS  AND  ALKALINE 
EARTHS. 

The  separation  of  these  bodies  in  the  caustic  state  is  a 
matter  of  difficulty  owing  to  the  great  tendency  they  possess 
to  become  converted  into  carbonates  ;  the  carbonates  of  lime, 
baryta  and  strontia,  moreover,  being  non-poisonous  in  their 
effects,  will  not  be  employed  with  criminal  intent,  and  the  car- 
bonates of  soda  and  potassa  are  extensively  used  as  pharma- 
ceutical preparations.  Notwithstanding  the  small  chances 
of  success,  the  isolation  of  the  compounds  under  consideration 
in  the  caustic  state  is  to  be  attempted. 

To  this  intent,  the  organs  to  be  analysed,  together  with  their 
contents,  are  placed  in  a  glass  retort  provided  with  a  receiver, 
water  added,  and  the  mixture  boiled.  The  distillate  will  con- 
tain the  ammonia  present.  When,  however,  putrefaction  has 
begun,  the  detection  of  this  compound  does  not  necessarily  in- 
dicate its  original  presence  in  the  suspected  materials.  If, 
after  an  hour's  boiling,  the  fluid  in  the  retort  possess  an  alkaline 
reaction,  it  is  to  be  examined  for  soda,  potassa,  strontia,  baryta 
and  lime.  The  undistilled  solution  is  filtered,  the  filtrate 
evaporated  to  dryness,  and  the  residual  mass  treated  with  alco- 
hol. By  this  treatment,  potassa  and  soda  go  in  solution,  lime, 
baryta  and  strontia  * — as  well  as  the  alkaline  carbonates — re- 
maining undissolved.  The  potassa  and  soda  are  separated  from 
the  other  salts  present  by  filtering  and  evaporating  the  alcohol- 
ic solution  to  dryness  and  then  calcining  the  residue  in  a  silver 
crucible.  The  mass,  which  should  still  be  alkaline,  is  then 
dissolved  in  dilute  sulphuric  acid.  If  the  solution  is  turbid, 
traces  of  baryta  or  strontia  may  still  be  present  and  should  be 

*  Baryta  and  strontia  dissolve  in  alcohol,  but  only  when  they  are   an- 
hydrous and  the  alcohol  is  absolute,  which  is  not  the  case  here. 


DETECTION  OF  ALKALIES.  53 

removed  by  filtration.  Some  hydrochloric  acid  and  solution 
of  bichloride  of  platinum  are  then  added  to  a  portion  of  the  filter- 
ed liquid  :  in  presence  of  potassa  a  yellow  precipitate  is  formed. 

Another  portion  is  treated  with  tartaric  acid  :  a  white  gran- 
ular precipitate  is  produced.  Hydrofluosilicic  acid  is  added  to 
a  third  portion  of  the  solution :  the  formation  of  a  gelatinous 
precipitate  is  a  further  indication  of  the  presence  of  potassa. 
If  the  preceding  tests  have  given  negative  results,  and  a  white 
precipitate  is  formed  by  the  addition  of  antimonate  of  potassa 
to  another  portion  of  the  solution,  soda  is  present.  In  both 
cases,  it  is  necessary  to  confirm  the  results  by  means  of  the 
spectroscope. 

The  above  reactions  are  distinctive  only  in  the  absence  of 
metals  precipitated  by  sulphuretted  hydrogen,  sulphide  of  am- 
monium or  carbonate  of  soda,  and  small  portions  of  the  solu- 
tion should  be  tested  with  these  reagents. 

In  order  to  detect  baryta,  strontia  and  lime,  the  residue, 
insoluble  in  alcohol  is  dissolved  in  dilute  nitric  acid,  and  an 
excess  of  carbonate  of  ammonia  added  to  the  solution  :  the 
three  bases,  if  present,  are  precipitated  as  carbonates.  The 
precipitate  formed  is  separated  from  the  solution  by  filtration, 
dissolved  on  the  filter  in  dilute  hydrochloric  acid,  and  the 
solution  then  filtered  and  divided  into  two  parts :  sulphuric 
acid  is  added  to  one,  the  fluid  filtered  from  the  precipitate  of 
sulphate  of  baryta  formed,  and  the  filtrate  treated  with  ammonia 
and  oxalate  of  ammonia.  If  lime  be  present, — although  its 
sulphate  is  not  easily  soluble — sufficient  will  be  contained  in 
the  filtrate  to  give  a  white  precipitate  of  oxalate  of  lime. 

The  remaining  portion  of  the  solution  is  evaporated  to  dry- 
ness,  and  the  residue  treated  with  absolute  alcohol.  Chloride 
of  strontium  goes  into  solution,  chloride  of  barium  remaining 
undissolved.  If  upon  evaporating  the  alcoholic  solution  a 


54 


LEGAL  CHEMISTRY. 


residue  is  obtained  which,  when  dissolved  in  water,  produces 
turbidity  in  a  solution  of  sulphate  of  lime,  strontia  is  present. 

The  residue,  insoluble  in  alcohol,  is  dissolved  in  water.  If 
a  precipitate  is  produced  by  the  addition  of  sulphuric  acid  or 
hydrofluosilicic  acid  to  the  solution,  baryta  is  present.  The  lat- 
ter reaction  distinguishes  baryta  from  strontia,  which  is  not  pre- 
cipitated by  hydrofluosilicic  acid.  Should  the  tests  mentioned 
above  fail  to  give  affirmative  results,  and  poisoning  by  means  of 
baryta  and  strontia  be  nevertheless  suspected,  these  compounds 
may  possibly  have  remained  in  the  materials  contained  in  the 
alimentary  canal,  in  the  state  of  insoluble  sulphates.  To  effect 
their  detection  under  these  circumstances  the  organic  sub- 
stances must  be  decomposed  by  means  of  sulphuric  acid.  The 
carbonaceous  residue  is  calcined  in  a  crucible  at  an  elevated 
temperature,  and  the  remaining  mass  treated  with  water.  In 
this  way,  a  solution  of  sulphides  of  barium  and  strontium  is  ob- 
tained, which  is  then  tested  as  directed  above. 

DETECTION  OF  CHLORINE,  BKOTCINE,  AND  IODINE. 

CHLORINE  AND  BLEACHING  CHLORIDES. 

The  detection  of  chlorine  is  very  difficult  owing  to  the  great 
tendency  it  possesses  to  become  converted  into  chlorides 
or  hydrochloric  acid,  and  it  is  only  when  found  in  a  free  state 
that  its  discovery  is  of  importance. 

In  case  the  gas  exists  uncombined  in  the  alimentary  canal, 
its  odor  will  be  perceptible,  and,  upon  boiling  the  suspected 
materials  with  water,  vapors  will  be  evolved  which  impart  a 
blue  color  to  paper  saturated  with  a  mixture  of  iodide  of  potas- 
sium and  starch  paste.  If  the  addition  of  sulphuric  acid  is 
necessary  in  order  to  produce  the  above  reactions,  there  is 


DETECTION  OF  BROMINE 


55 


reason  to  suspect  the  presence  of  "  chloride  of  lime"  or  "  Eau 
de  Javelle."  * 

BROMINE. 

In  case  bromine  exists  in  a  free  state  at  the  time  the  au- 
topsy is  made,  its  presence  will  be  detected  by  the  reddish  color 
and  unpleasant  odor  it  possesses.  Its  isolation  is  accomplish- 
ed by  treating  the  materials  with  bisulphide  of  carbon  which, 
upon  dissolving  the  bromine,  acquires  a  red  color.  If  potassa 
is  then  added  to  the  solution,  it  combines  with  the  bromine 
and,  upon  evaporating  the  decanted  fluid,  calcining  the  residue, 
and  treating  it  with  water,  a  solution  of  bromide  of  potassium 
is  obtained.  Upon  adding  chlorine-water  and  ether  to  a 
portion  of  the  fluid,  and  shaking  the  mixture,  the  bromine  is 
liberated  and  is  dissolved  by  the  ether.  The  etherial  solution 
of  bromine,  which  possesses  a  reddish-yellow  color,  does  not 
mingle  with,  but  floats  upon  the  surface  of  the  colorless  aque- 
ous solution. 

If  nitrate  of  silver  is  added  to  another  portion  of  the 
aqueous  solution  of  bromide  of  potassium,  a  precipitate  of 
bromide  of  silver,  soluble  in  ammonia,  is  formed. 

In  case  the  bromine  has  been  converted  into  a  bromide,  it 
is  necessary  to  boil  the  alimentary  canal  and  the  articles  of 
food  contained  therein  with  water.  The  fluid  is  next  filtered 
and  agitated  with  chlorine-water  and  ether.  The  liberated 
bromine  is  dissolved  by  the  ether,  which  acquires  a  reddish- 
yellow  color.  Upon  decanting  the  solution,  and  treating  it 
with  potassa,  bromide  of  potassium  is  formed,  and  can  be  de- 
tected as  directed  above. 

*  The  so-called  "  chloride  of  lime"  is  probably  either  a  mixture  of 
chloride  and  hypochlorite  of  calcium  or  an  oxydichloride  of  the  metal ; 
"  Eau  de  Javelle  "  is  the  corresponding  potassium  compound. —  Trans. 


56  LEGAL  CHEMISTRY. 

IODINE. 

The  detection  of  iodine  is  accomplished  by  a  process  al- 
most identical  with  the  above.  The  isolation  of  the  iodine 
having  been  effected,  it  remains  to  be  ascertained  that  it 
imparts  a  blue  color  to  starch  paste,  and  a  violet  color  to 
bisulphide  of  carbon. 

DETECTION  OF  METALS. 

Under  this  head  we  will  indicate  the  systematic  course  of 
analysis  to  be  pursued,  supposing  a  mixture  of  several  metals 
including  arsenic  and  antimony,  to  be  under  examination. 

The  organic  substances  are  first  destroyed  by  means  of 
chlorate  of  potassa  and  hydrochloric  acid.  When  this  is  ac- 
complished, the  excess  of  chlorine  is  removed  by  boiling  and 
the  liquid  filtered.  The  portion  remaining  on  the  filter  is 
preserved  :  it  contains  all  the  silver  and  a  large  portion  of  the 
lead,  if  these  metals  are  present.  We  will  designate  the  resi- 
due as  A,  the  filtrate  as  B. 

TREATMENT  OF  RESIDUE  A. 

The  residue  is  calcined  with  a  little  carbonate  of  soda  and 
cuttings  of  pure  Swedish  filtering  paper,  the  chlorides  pre- 
sent being  reduced  to  the  metallic  state  by  this  treatment.  The 
residue  is  next  taken  up  with  water  acidulated  with  nitric 
acid,  and  the  solution  filtered.  An  insoluble  residue,  that 
may  remain,  is  washed  with  hot  water  until  the  wash-water 
ceases  to  precipitate  solution  of  nitrate  of  silver,  and  dried. 
It  is  then  dissolved  in  boiling  nitric  acid,  the  solution  diluted 
with  water,  and  filtered.  * 

*  If  an  insoluble  residue  remains  by  the  treatment  with  nitric  acid,  it 


DETECTION  OF  METALS.  57 

Sulphuric  acid  is  added  to  the  filtrate  :  if  no  preci- 
pitate forms,  the  absence  of  lead,  in  the  residue  A,  is  indicated. 
If,  on  the  contrary,  a  precipitate  is  produced,  it  is  collected 
upon  a  filter  and  washed.  In  order  to  make  sure  that  the  preci- 
pitate consists  of  sulphate  of  lead,  it  is  treated  with  a  solution 
of  tartrate  of  ammonia  :  it  should  dissolve,  forming  a  solution 
in  which  sulphuretted  hydrogen  produces  a  black  precipitate. 

The  fluid  which  has  failed  to  be  precipitated  by  the  ad- 
dition of  sulphuric  acid,  or  the  filtrate  separated  from  the  preci- 
pitate formed,  can  contain  only  silver.  Upon  adding  hydro- 
chloric acid,  this  metal  is  thrown  down  as  a  caseous  white  preci- 
pitate, which  is  soluble  in  ammonia,  but  insoluble  in  boiling 
nitric  acid,  and  blackens  upon  protracted  exposure  tonight. 
The  formation  of  a  precipitate  possessing  these  properties, 
leaves  no  doubt  as  to  the  presence  of  silver. 

Remark. — In  the  operations  described  above,  as  well  as  in 
those  following,  the  difficulty  in  separating  minute  precipitates 
from  the  filter  is  often  experienced.  When  the  precipitate  is 
to  be  dissolved  in  reagents  that  do  not  affect  the  paper,  such 
as  ammonia,  tartrate  of  ammonia,  and  dilute  acids,  it  can  be 
brought  in  solution  directly  on  the  filter.  In  cases,  however, 
where  reagents  which  attack  the  paper  are  employed,  the 
precipitate  should  be  separated.  This  is  accomplished  by 
mixing  a  small  quantity  of  pure  silica,  obtained  by  the  de- 
composition of  fluoride  of  silicium  by  water,  with  the  solution, 
before  filtering.  The  precipitate  becomes  intimately  mixed  with 


may  consist  of  tin.  In  this  case,  it  is  dissolved  in  aqua  regia,  the  metal 
precipitated  by  immersing  a  plate  of  zinc  in  the  solution  and  then  re-dis- 
solved in  boiling  hydrochloric  acid.  Upon  adding  chloride  of  gold  to  the 
solution  so  obtained,  a  purple  precipitate  is  formed.  Sulphuretted  hy- 
drogen produces  a  brown  precipitate,  soluble  in  sulphide  of  ammonium,  in 
presence  of  tin. 

3* 


58  LEGAL  CHEMISTRY. 

the  silica,  and  can  then  be  readily  removed  from  the  paper. 
The  presence  of  silica  does  not  interfere,  it  being  insoluble  in 
the  reagents  commonly  made  use  of. 

TREATMENT  OF  FILTRATE  B. 

A  current  of  sulphuretted  hydrogen  is  conducted  for  twelve 
hours  through  the  solution,  which  is  kept  at  a  temperature  of 
70°.  by  means  of  a  water-bath.  The  flask  containing  the 
liquid  is  then  closed  with  a  piece  of  paper,  and  allowed  to 
remain  in  a  moderately  warm  place  until  the  odor  of  the  gas 
is  no  longer  perceptible.  The  solution  is  next  filtered  with 
the  precaution  mentioned  in  the  preceding  remark,  and  the 
precipitate  (a)  thoroughly  washed.  The  water  used  in  this 
operation  is  united  to  the  nitrate,  and  the  fluid  (b)  examined 
as  directed  further  on,. 

TREATMENT  OF  PRECIPITATE  a. 

In  order  to  free  the  precipitate  from  the  organic  substances 
possibly  present,  at  the  same  time  avoiding  a  loss  of  any 
metal,  it  is  dried,  moistened  with  nitric  acid,  and  the  mass 
heated  on  a  water-bath.  Some  Swedish  filtering  paper  is  next 
added,  the  mixture  well  impregnated  with  sulphuric  acid,  and 
then  maintained  for  several  hours  at  a  temperature  of  about 
170°.  until  a  small  portion  (afterwards  returned)  gives  a  colorless 
solution  when  treated  with  water.  The  residue  is  now  heated 
with  a  mixture  of  one  part  of  hydrochloric  acid  and  eight 
parts  of  water,  the  liquid  filtered,  the  matter  remaining  undis- 
solved  washed  with  dilute  hydrochloric  acid,  and  the  washings 
united  with  the  filtrate. 

The  residue  i.  and  the  solution  n.  are  separately  o.tm- 
ined  as  directed  below. 


DETECTION  OF  METALS. 


RESIDUE    I. 


59 


This  may  contain  lead,  mercury,  tin,  bismuth  and  antimo- 
ny. It  is  heated  for  a  considerable  time  with  aqua  regia,  the 
solution  filtered,  and  the  second  residue,  should  one  remain, 
washed  with  dilute  hydrochloric  acid.  If  the  second  residue 
is  fused  with  cyanide  of  potassium,  the  compounds  present  are 
reduced  to  the  metallic  state.  The  liberated  metals  are  treated 
with  nitric  acid,  which  dissolves  lead,  but  leaves  tin  as  insoluble 
metastannic  acid.  The  nitrate  of  lead  is  then  filtered  from 
the  metastannic  acid,  and  both  metals  are  identified  as  de- 
scribed in  the  treatment  of  residue  A. 

The  solution,  obtained  by  the  action  of  aqua  regia  on  resi- 
due I,  is  treated  with  sulphuretted  hydrogen.  The  tin  and  an- 
timony are  separated  from  the  lead,  mercury  and  bismuth  by 
treating  the  precipitate  produced  with  sulphide  of  ammonium, 
which  dissolves  only  the  sulphides  of  the  first  two  metals. 
The  solution  in  sulphide  of  ammonium  is  af  terwards  examined 
for  these  metals,  as  directed  under  the  head  of  solution  IV., 
the  search  for  arsenic,  however,  being  here  omitted. 

Upon  treating  the  residue  insoluble  in  sulphide  of  ammo- 
nium with  nitric  acid,  lead,  copper  and  bismuth  go  into  solu- 
tion, mercury  remaining  undissolved.  The  liquid  is  filtered, 
and  the  undissolved  mercury  submitted  to  the  special  exami- 
nation previously  described. 

Sulphuric  acid  is  added  to  the  solution  and  the  precipitate 
of  sulphate  of  lead  formed,  separated,  washed,  and  examined 
as  directed  while  treating  of  residue  A. 

Finally,  the  solution  separated  from  the  lead  is  tested  for 
bismuth  and  copper,  as  in  examination  of  precipitate  III. 


60  LEGAL  CHEMISTRY. 

SOLUTION  II. 

The  solution  is  concentrated  by  heating  on  a  water-bath,  a 
small  quantity  of  carbonate  of  soda  cautiously  added  to  a  por- 
tion, and  notice  taken  if  a  precipitate  forms.  The  part  taken 
is  then  acidulated  with  a  little  hydrochloric  acid,  returned  to  the 
principal  solution,  and  sulphuretted  hydrogen  conducted  through 
the  fluid,  as  in  the  examination  of  solution  B.  In  case  a  pre- 
cipitate fails  to  form,  all  metals  are  absent ;  if,  on  the  contrary, 
a  precipitate  (V)  is  produced,  it  is  examined  as  directed  below. 

EXAMINATION  OF  PRECIPITATE  C. 

If  the  solution  merely  became  turbid,  or  the  precipi- 
tate formed  was  of  a  pure  white  color,  it  consists  probably 
of  sulphur.  It  is,  however,  indispensable,  even  in  this 
case,  to  collect  the  precipitate  and  examine  it  for  arsenic. 
Provided  it  is  of  a  pure  yellow  color,  it  is  treated  with  ammonia. 
In  case  it  is  entirely  dissolved  by  this  treatment,  and  the 
addition  of  carbonate  of  ammonia  failed  to  produce  a  pre- 
cipitate in  solution  II.,  it  is  certain  that  arsenic,  and  no  other 
metal,  is  present.  Under  these  circumstances,  the  ammon- 
iacal  solution  is  examined  as  directed  in  the  article  on  the 
detection  of  arsenic.  If,  on  the  other  hand,  the  precipitate  is 
not  yellow,  or  being  yellow,  is  but  imperfectly  soluble  in  am- 
monia, and  a  precipitate  was  formed  by  the  addition  of  carbon- 
ate of  ammonia  to  solution  II.,  it  is  necessary  to  likewise 
search  for  tin,  antimony,  mercury,  copper,  bismuth  and  cad- 
mium. In  this  case,  the  precipitate  is  placed  in  a  small  flask, 
allowed  to  digest  for  several  hours  with  ammonia  and  sulphide 
of  ammonium  in  a  moderately  warm  place,  and  the  solution  fil- 
tered. 


DETECTION  OF  METALS.  61 

The  remaining  residue  (III.)  is  washed,  labelled,  and  pre- 
served for  subsequent  examination  ;  the  filtrate  (IV.)  is  treat- 
ed as  directed  below. 


TREATMENT   OF    SOLUTION  IV. 

The  solution,  to  which  the  water  used  in  washing  the  resi- 
due has  been  added,  is  evaporated  to  dryness,  the  residue 
obtained  taken  up  with  pure  fuming  nitric  acid,  and  the  liquid 
again  evaporated.  The  second  residue  is  next  saturated  with 
a  solution  of  carbonate  of  soda.  A  mixture  of  i  part  of  car- 
bonate and  2  of  nitrate  of  soda  is  then  added,  the  mixture 
evaporated  to  dryness,  and  the  residual  mass  heated  to  fusion. 
The  fused  mass,  when  cold,  is  treated  with  cold  water,  and  any 
remaining  residue  washed  with  a  mixture  of  equal  parts  of  al- 
cohol and  water.  The  filtered  fluids  are  now  evaporated  in  order 
to  remove  the  alchohol,  sulphuric  acid  is  then  added,  and  the 
mixture  heated  until  white  fumes  of  the  acid  begin  to  evolve.  In 
this  way  the  complete  expulsion  of  the  nitric  acid  present  is 
rendered  certain.  When  cold,  the  residue  is  treated  with  wa- 
ter and  the  solution  introduced  into  Marsh's  apparatus,  or,  in 
case  a  quantitative  estimation  of  the  arsenic  is  desired,  it  is 
treated  with  sulphuretted  hydrogen  and  the  weight  of  the  pre- 
cipitate formed  determined,  as  directed  under  the  detection  of 
arsenic. 

Should  a  residue  insoluble  in  water  remain,  it  may  contain 
tin,  antimony  and  traces  of  copper.  Upon  dissolving  it  in  aqua 
regia  and  placing  a  sheet  of  pure  zinc  in  the  solution,  these 
metals  are  thrown  down  in  the  metallic  state.  The  precipitate 
is  collected,  the  zinc  present  completely  removed  by  treatment 
with  dilute  hydrochloric  acid,  and  the  residue  boiled  with  con- 
centrated hydrochloric  acid  which  dissolves  the  tin  present 


62  LEGAL  CHEMISTRY. 

The  fluid  is  filtered  and  the  filtrate  tested  for  this  metal  by 
adding  solution  of  chloride  of  gold,  which,  in  its  presence,  pro- 
duces a  purple  precipitate,  and,  by  treating  it  with  sulphurated 
hydrogen,  which  forms  a  brown  precipitate,  soluble  in  sulphide 
of  ammonium. 

If  the  residue,  insoluble  in  concentrated  hydrochloric  acid, 
is  thoroughly  washed  and  then  treated  with  nitric  acid,  the 
copper  present  goes  in  solution.  The  fluid  is  filtered,  and  am- 
monia added  to  the  filtrate :  in  presence  of  copper,  the  solution 
acquires  a  blue  color,  and  .gives  a  reddish  precipitate  upon  ad- 
dition of  ferrocyanide  of  potassium. 

Antimony,  if  present,  remains  by  the  treatment  with  nitric 
acid  as  an  insoluble  intermediate  oxide.  This  is  dissolved  in 
hydrochloric  acid,  in  which  it  is  now  soluble,  and  the  solution 
introduced  into  Marsh's  apparatus. 

TREATMENT   OF   PRECIPITATE   III. 

This  precipitate  may  contain  the  sulphides  of  mercury,  cop- 
per, cadmium  and  bismuth.  Upon  treating  it  with  nitric  acid, 
all  but  the  sulphide  of  mercury  are  dissolved.  In  case  no  resi- 
due remains,  the  absence  of  mercury  is  indicated  ;  if,  on  the 
other  hand,  a  residue  is  left,  it  is  well  washed,  dissolved  in 
aqua  regia,  and  the  solution  examined,  either  by  means  of 
Sinithson's  pile,  or  in  the  apparatus  of  Flandin  and  Danger. 
(  Vide  Detection  of  Mercury?) 

Whether  a  residue  remains  or  not,  an  excess  of  ammonia 
is  next  added  to  the  filtered  solution  in  nitric  acid  :  the  forma- 
tion of  a  permanent  precipitate  denotes  the  presence  of  bis- 
muth. In  this  case,  the  fluid  is  filtered,  and  the  alkaline  filtrate 
further  tested  for  copper  and  cadmium.  For  this  purpose,  cy- 
anide of  potassium  is  added,  and  sulphuretted  hydrogen  con- 


DETECTION  OF  METALS.  63 

ducted  through  the  filtrate  :  if  cadmium  be  present,  a  yellow 
precipitate  is  produced,  copper  not  being  thrown  down  in  pre- 
sence of  an  alkaline  cyanide.  The  precipitate  of  sulphide  of 
cadmium  is  separated  from  the  solution  by  filtration,  and  the 
filtrate  saturated  with  hydrochloric  acid.  Copper,  if  present, 
is  now  precipitated  as  sulphide  :  its  separation  is  completed 
by  conducting  sulphuretted  hydrogen  through  the  fluid. 

The  precipitate  is  collected,  washed,  dissolved  in  nitric  acid, 
and  its  identity  established  as  previously  directed.  If  the 
metal  be  present  in  sufficient  quantity,  it  should  be  obtained 
in  a  metallic  state  upon  a  plate  of  iron  ;  it  is  then  coherent, 
possesses  its  natural  color,  and  can  conveniently  be  exhibited 
to  the  Jury. 

TREATMENT  OF  SOLUTION  b. 

This  solution  may  contain  :  cobalt,  nickel,  iron,  manganese, 
chromium,  zinc  and  aluminium.  Of  these,  only  zinc  and 
chromium  are  poisonous  ;  the  search  for  these  two  metals  is 
therefore  all  that  is  necessary  in  criminal  cases.  The  solution 
is  treated  with  a  slight  excess  of  ammonia,  sulphide  of  ammo- 
nium added,  and  the  fluid,  after  being  allowed  to  stand  for 
several  hours,  filtered.  The  precipitate  may  consist  of  sul- 
phide of  zinc  and  hydrated  oxide  of  chromium,  as  well  as  of 
traces  of  sulphide  of  iron  and  phosphate  of  lime.  If  the  sus- 
pected materials  contained  a  chromate,  this  salt,  in  presence 
of  hydrochloric  acid  and  sulphuretted  hydrogen,  would  be  con- 
verted into  sesquichloride  of  chromium  a  compound  which  is 
precipitated  by  sulphide  of  ammonium  as  a  hydrated  oxide. 

The  precipitate  is  washed  with  water,  to  which  a  little 
sulphide  of  ammonium  is  added,  then  dried,  and  fused  with 
four  times  its  weight  of  a  mixture  of  equal  parts  of  carbonate 
and  nitrate  of  potassa.  After  the  mass  has  remained  in  a 


64  LEGAL  CHEMISTRY. 

state  of  fusion  for  a  quarter  of  an  hour,  it  is  treated  with 
boiling  water,  mixed  with  a  little  alcohol,  in  order  to  decompose 
the  manganate  that  would  be  present  were  manganese  con- 
tained in  the  materials  under  examination.  The  alcohol  is 
then  expelled  by  boiling  the  fluid,  and  the  solution  filtered. 
The  filtrate  may  contain  phosphate  of  potassa,  originating 
from  the  phosphate  of  lime  present,  and  chromate  of  potassa^ 
resulting  from  the  oxidation  of  the  sesquioxide  of  chromium. 
In  presence  of  the  latter  compound,  the  following  reactions 
will  occur  in  the  solution:  ist,  Upon  acidulation  with  acetic 
acid  and  addition  of  solution  of  acetate  of  lead,  a  yellow 
precipitate,  soluble  in  potassa,  is  formed  ;  2nd.,  if  hydrochloric 
acid  is  added  and  sulphuretted  hydrogen  conducted  into  the 
solution,  the  latter  acquires  a  green  color,  and,  upon  adding 
ammonia,  a  bluish-grey  precipitate  of  chromic  hydrate  is 
produced  ;  3rd.,  if  nitrate  of  silver  is  added  to  the  solution, 
a  brick-red  precipitate  is  formed. 

Ths  precipitate  remaining  on  the  filter,  may  consist  of 
zinc,  mixed  with  the  oxides  of  iron,  nickel,  cobalt,  aluminium 
and  manganese.  It  is  dissolved  in  boiling  hydrochloric  acid, 
acetate  of  soda  added,  and  the  fluid  boiled  until  no  further 
precipitation  occurs.  The  iron  is  now  completely  separated. 
The  solution  is  then  filtered,  the  precipitate  washed,  and  an 
excess  of  potassa  added  to  the  filtrate ;  if  the  solution  contains 
cobalt,  nickel  or  manganese — which  is  improbable — a  perma- 
nent precipitate  is  formed.  This  is  separated  from  the  fluid  by 
filtration :  its  further  examination  is,  however,  unnecessary,  as 
the  metals  of  which  it  consists  are  not  poisonous.  The 
filtrate  may  contain  aluminium  and  zinc.  The  latter  metal  is 
detected  by  acidulating  the  filtrate  with  acetic  acid,  and  adding  a 
solution  of  sulphuretted  hydrogen  :  in  presence  of  zinc  a  white 
precipitate  of  its  sulphide  is  formed. 


v 

DETECTION  OF  ALKALOIDS.  65 

In  case  organic  substances  are  present,  the  precipitation  of 
chromium  by  sulphide  of  ammonium  may  possibly  have  been 
hindered,  and  the  metal  have  passed  into  the  filtrate.  When, 
therefore,  chromium  is  not  detected  in  the  precipitate,  the 
filtrate  should  also  be  examined.  For  this  purpose,  the  fluid 
is  evaporated  to  dryness,  and  the  residue  obtained  fused  with 
a  mixture  of  nitrate  and  carbonate  of  soda.  The  fused  mass 
is  then  taken  up  with  water,  the  solution  acidulated  with 
acetic  acid,  and  a  solution  of  acetate  of  lead  added :  if 
chromium  be  present,  a  yellow  precipitate,  soluble  in  potassa, 
is  produced. 

DETECTION  OF  ALKALOIDS  A!VD   XO1TIK  ILL-DEFINED 
ORGANIC     SUBSTANCES.* 

A  general  method  for  effecting  the  detection  of  alkaloids 
was  first  proposed  by  Stas.  Since  the  publication  of  this 
method,  modifications  to  it  have  been  recommended  by  Ottot 
and  by  L.  Uslar  and  y.  Erdnian.  Other  processes  have 
been  suggested  by  Rodgers  and  Girwood,  by  E.  Prollius,  and 
by  Graham  and  Hofman.  The  latter  will  doubtless  become 
general  in  their  application  ;  but  up  to  the  present  time  they 
have  been  employed  exclusively  in  the  detection  of  strychnine. 
Dialysis  has  also  been  recently  applied  in  the  separation  of 
alkaloids. 

STAS'S   METHOD. 

This  method  is  based  upon  the  facts  :  (#),  that  the  acid  salts 
of  the  alkaloids,  especially  those  containing  an  excess  of  tar- 


*  Colchicine,  picrotoxine  and  digitaline. 


66  LEGAL  CHEMISTRY. 

taric  or  oxalic  acids,  are  decomposed  by  caustic  alkalies  and 
by  the  bicarbonates  of  soda  andpotassa  ;  (b),  that  the  alkaloids, 
when  liberated  in  this  manner,  are  combined  with  a  certain 
amount  of  water  which  determines  their  solution  in  ether, 
although,  in  a  desiccated  state  they  may  be  insoluble  in  this 
menstruum  ;  (V),  that  they  may  be  extracted  from  their  aqueous 
solutions  by  agitation  with  ether. 

Stas's  original  method  is  as  follows :  The  suspected  sub- 
stances, if  organs  are  contained,  are  cut  into  fine  shreds,  then 
mixed  with  absolute  alcohol,  0.5  to  2.  grammes  of  tartaric  or 
oxalic  acid  added  and  the  whole  introduced  into  a  flask  and 
heated  at  a  temperature  of  60°  to  75°.  When,  quite  cold, 
the  mixture  is  filtered,  and  the  undissolved  portion  remaining 
on  the  filter  washed  with  absolute  alcohol,  the  washings  being 
added  to  the  filtrate.  The  alcoholic  solution  is  evaporated, 
either  by  placing  it  under  a  bell-jar  connected  with  an  air- 
pump,  or  by  passing  a  current  of  air,  having  a  temperature  not 
exceeding  35°  over  it,  until  reduced  to  a  quarter  of  its  original 
volume :  the  complete  expulsion  of  the  alcohol  being  then 
rendered  certain.  If  insoluble  matter  separates  during  this 
operation,  the  concentrated  fluid  is  passed  through  a  moistened 
filter,  the  water  used  in  washing  the  residue  being  united  to 
the  filtrate  which  is  then  evaporated  to  dryness  by  aid  of  the 
air-pump  or  by  placing  the  fluid  iu  a  bell-jar  over  concentrated 
sulphuric  acid.  When  the  evaporation  is  completed,  the 
residue  is  treated  with  absolute  alcohol,  the  alcohol  allowed  to 
evaporate  at  the  ordinary  temperature  of  the  air,  and  the 
second  residue  dissolved  in  the  smallest  possible  amount  of 
water.  The  fluid  thus  obtained  is  placed  in  a  test-tube,  and  a 
concentrated  solution  of  bicarbonate  of  soda  added  so  long 
as  effervescence  takes  place.  Ether  is  then  added,  the  mix- 
ture thoroughly  shaken,  and  after  it  has  remained  at  rest  for 


DETECTION  OF  ALKALOIDS.  67 

some  time,  a  small  portion  of  the  supernatant  ether  removed 
and  evaporated  on  a  watch-glass :  the  residue  obtained  will 
consist  of  the  alkaloid  present.  Two  cases  are  now  possible : 
the  alkaloid  is  a  solid,  or  it  is  a  liquid  and  is  volatile. 

The  further  treatment  of  the  solution  is  modified  according 
to  these  circumstances,  • 


a.    THE    ALKALOID    IS    LIQUID    AND   VOLATILE. 

If,  upon  the  evaporation  of  the  ether,  oily  streaks  were 
left  on  the  watch-glass,  a  volatile  alkaloid  is  probably  pres- 
ent. 

In  this  case,  a  solution  of  caustic  potassa  is  added  to  the 
test-tube,  the  mixture  shaken,  the  supernatant  ether  decanted  * 
into  a  flask  and  the  remaining  solution  again  washed  with 
ether  until  the  last  portion  fails  to  leave  a  residue  upon 
evaporation.  The  etherial  fluids  are  then  united,  and  two 
cubic  centimetres  of  water,  acidulated  with  one-fifth  of  its 
weight  of  sulphuric  acid,  added.  This  acid  retains  the  alka- 
loid, which  is  now  in  the  state  of  a  pure  acid-sulphate  soluble 
in  water,  the  animal  matters  present  remaining  dissolved  in 
the  ether.  The  ether,  in  which  some  sulphate  of  conia  may 
be  contained — although  the  greater  portion  of  this  compound 
would  remain  in  the  aqueous  solution — is  then  decanted.  The 
remaining  aqueous  solution  of  the  pure  sulphate  of  the  alka- 
loid is  placed  in  a  test-tube,  a  solution  of  caustic  potassa  and 
some  ether  added,  and  the  mixture  well  shaken.  The  ether 
is  next  decanted  and  allowed  to  spontaneously  evaporate  in  a 


*  The  necessity  of  decanting   etherial   and  other  solutions  is  advanta- 
geously obviated  by  the  use  of  a  pipette. —  Trans. 


68  LEGAL  CHEMISTRY. 

dry  place  at  a  very  low  temperature,  and  the  ammonia  possibly 
present  is  then  removed  by  placing  the  vessel  containing  the 
residue  over  sulphuric  acid.  The  residue  now  obtained  con- 
sists of  the  alkaloid  present  in  a  state  of  purity,  and  can 
be  directly  identified  by  means  of  the  reactions  described  fur- 
ther on. 

b.    THE   ALKALOID    IS   SOLID. 

It  sometimes  occurs  that  ether  fails  to  take  up  all  of  the 
alkaloid  present  in  the  fluid  treated  with  bicarbonate  of  soda. 
Under  these  circumstances  the  fluid  should  be  mixed  with 
caustic  potassa,  the  mixture  shaken,  and  the  ether  decanted  ; 
this  operation  being  repeated  several  times,  until  the  entire 
amount  of  the  alkaloid  is  removed  ;  the  ethereal  fluids  are  then 
united  in  a  capsule,  and  allowed  to  spontaneously  evaporate. 
The  result  of  the  evaporation  may  be  solid ;  more  frequently, 
however,  a  milky  liquid  remains  which  restores  the  blue  color 
to  reddened  litmus  paper;  if  so,  the  presence  of  a  vege- 
table alkaloid  is  certain.  In  order  to  purify  the  residue, 
a  few  drops  of  water,  slightly  acidulated  with  sulphuric  acid, 
are  added  to  the  capsule,  and  the  latter  turned,  so  as  to  bring 
the  fluid  in  contact  with  the  substance  at  all  points  ;  in  this 
manner  a  colorless  and  limpid  fluid  is  obtained,  the  fatty 
substances  adhering  to  the  dish.  The  liquid  is  decanted  into 
a  second  capsule,  the  remaining  residue  washed  with  a  little 
acidulated  water,  and  the  washings  likewise  added  to  the 
principal  solution.  The  fluid  is  now  evaporated  either  in 
vacua,  or  over  sulphuric  acid,  to  about  three-fourths  of  its 
original  volume  a  concentrated  solution  of  neutral  carbon- 
ate of  potassa  added,  and  the  mixture  treated  with  absolute 
alcohol,  which  dissolves  the  liberated  alkaloid,  and  separates 


DETECTION  OF  ALKALOIDS.  69 

it  from  the  sulphate  of  potassa  formed  and  the  excess  of 
carbonate  of  potassa.  The  alcoholic  solution  is  decanted  and 
allowed  to  evaporate  in  vacuo  or  in  the  air :  the  alkaloid  now 
crystallizes  out  in  a  state  suitable  for  further  examina- 
tion. 

MODIFICATIONS    TO    STAS'S    METHOD,    PROPOSED    BY    OTTO. 

In  Stas's  method,  the  loss  of  morphine  is  possible,  for,  if 
ether  is  not  added  immediately  after  the  addition  of  carbonate 
of  soda,  this  alkaloid  crystallizes  and  is  then  no  longer  soluble 
in  that  menstruum  ;  and,  if  the  ethereal  solution  is  not  quickly 
decanted,  the  portion  dissolved  will  likewise  separate  out  in 
small  crystals.  In  both  cases,  morphine  will  remain  in  the 
aqueous  solution  from  which  the  other  alkaloids  have  been 
extracted  by  the  ether.  M.  Otto  recommends  the  addition  of 
chloride  of  ammonium  and  a  little  soda-lye,  in  order  to  dis- 
solve the  alkaloid.  Upon  allowing  the  solution  so  obtained 
to  stand  for  some  time  exposed  to  the  air,  crystals  of  morphine 
are  deposited. 

According  to  the  same  authority,  it  is  advisable  to  omit 
the  distinction  drawn  by  Stas  between  volatile  and  fixed 
alkaloids,  and  submit  both  to  the  treatment  recommended  for 
those  that  are  volatile. 

Otto  also  recommends  the  agitation  of  the  fluid  contain- 
ing the  oxalates  or  tartrates  of  the  alkaloids  with  ether,  pre- 
viously to  their  separation  by  means  of  bicarbonate  of  soda. 
By  this  treatment  the  elimination  of  the  coloring  matter  pres- 
ent— as  well  as  of  colchicine,  digitaline,  picrotoxine,  traces  of 
atrofine,  and  various  impurities — is  accomplished.  As  soon 
as  the  ether  ceases  to  become  colored  and  to  leave  a  residue 
upon  evaporation,  alkali  is  added,  and  the  operation  con- 
cluded as  usual.  In  this  way  the  alkaloid  is  obtained,  almost 


70  LEGAL  CHEMISTRY. 

directly,  in  a  pure  condition.  This  last  modification  appears 
to  us  to  be  a  very  happy  one,  inasmuch  as  it  greatly  facilitates 
the  purification  of  the  alkaloid  present. 


MODIFICATIONS   TO    STAS'S    METHOD,    PROPOSED    BY    USLAR    AND 

ERDMAN. 

i  st.  The  materials  to  be  examined  are  brought  to  the  con- 
sistence of  a  thin  paste,  and  digested  for  about  two  hours 
with  water,  to  which  some  hydrochloric  acid  has  been  added, 
at  a  temperature  of  60°  to  80°.  The  mixture  is  then  filtered 
through  a  moistened  linen  cloth,  and  the  residue  washed  with 
warm  acidulated  water ;  the  washings  being  added  to  the 
solution. 

2nd.  Some  pure  quartz  sand — or,  preferably,  silica  prepared 
by  the  decomposition  of  fluoride  of  silicium — is  added  to  the 
filtrate,  the  fluid  supersaturated  with  ammonia,  and  evapo- 
rated to  dryness  over  a  water-bath  :  the  addition  of  silica  ren- 
ders the  residue  friable. 

3rd.  The  residue  is  boiled  repeatedly  with  amylic  alcohol, 
which  extracts  all  the  alkaloid  present  as  well  as  the  fatty 
and  coloring  matters,  and  the  extracts  filtered  through  filter 
paper  that  has  been  moistened  with  amylic  alcohol. 

4th.  The  filtered  fluid  is  thoroughly  agitated  with  ten  or 
twelve  times  its  volume  of  almost  boiling  water  acidulated 
with  hydrochloric  acid  :  the  hydrochlorate  of  the  alkaloid  pres- 
ent goes  into  the  aqueous  solution,  the  fatty  and  coloring 
substances  remaining  dissolved  in  the  oily  supernatant  layer. 
The  latter  is  separated  by  means  of  a  pipette,  and  the  acid 
aqueous  solution  shaken  with  fresh  quantities  of  amylic 
alcohol  until  completely  decolorized. 

5th.  The  aqueous  solution  is  then  concentrated,  ammonia 


DETECTION  OF  ALKALOIDS.  7 1 

added,  and  the  mixture  well  shaken  with  warm  amylic  alcohol, 
in  which  the  alkaloid  dissolves.  As  soon  as  the  solution 
forms  a  supernatant  layer  upon  the  surface  of  the  fluid,  it  is 
drawn  off  with  a  pipette  and  evaporated  on  a  water-bath.  In 
this  manner,  the  alkaloid  is  usually  obtained  in  a  sufficient 
state  of  purity  to  admit  of  its  immediate  identification  ;  if, 
however,  a  small  portion  turns  brown  when  treated  with  concen- 
trated sulphuric  acid,  the  process  of  purification  must  be 
repeated.  Under  these  circumstances  it  is  re-dissolved  in 
dilute  hydrochloric  acid,  the  solution  repeatedly  shaken  with 
amylic  alcohol,  in  order  to  extract  the  impurities  present,  and 
the  alkaloid  then  extracted  with  ammonia  and  amylic  alcohol, 
as  previously  directed. 

The  method  of  von  Uslar  and  Erdman  differs  from  that  of 
Stas  merely  in  the  substitution  of  amylic  alcohol  for  ether, 
and  of  hydrochloric  acid  for  oxalic  or  tartaric  acid.  It  offers 
no  advantages  over  Stas's  method  if  the  alkaloids  present  are 
soluble  in  ether  but  is  even  less  advantageous  in  this  case, 
inasmuch  as  its  execution  requires  a  longer  time.  In  cases 
where  the  detection  of  morphine,  or  an  unknown  alkaloid,  is 
desired,  the  use  of  amylic  alcohol  instead  of  ether  is,  it  is 
true,  preferable  ;  still,  with  the  exercise  of  care,  ether  can  also 
be  employed,  and,  as  this  process  greatly  facilitates  examina- 
tions when  no  clew  to  the  poison  present  exists  and  all  alka- 
loids may  possibly  be  absent,  we  prefer  it  to  the  one  just 
described. 

RODGERS    AND   GIRDWOOD's    METHOD. 

This  method — which  as  yet  has  only  been  employed  in 
the  detection  of  strychnine — is  based  upon  the  solubility  of  this 
alkaloid  in  chloroform.  The  substances  under  examination 


7  2  LEGAL  CHEMISTRY. 

are  digested  with  dilute  hydrochloric  acid,  and  the  mixture 
filtered.  The  filtrate  is  then  evaporated  to  dryness  on  the 
water-bath,  the  residue  taken  up  with  pure  alcohol,  the  alco- 
holic solution  evaporated,  the  second  residue  treated  with 
water,  and  the  solution  so  obtained  filtered.  The  filtrate  is 
next  supersaturated  with  ammonia,  and  well  shaken  with 
chloroform,  which,  upon  being  separated  by  means  of  a  pipette 
and  evaporated,  leaves  the  alkaloid  in  an  impure  state.  Con- 
centrated sulphuric  acid  is  then  poured  upon  the  alkaloid : 
the  latter  is  not  affected  by  this  treatment,  whereas  the  foreign 
organic  substances  present  are  carbonized.  After  the  lapse 
of  several  hours,  the  mixture  is  treated  with  water,  the  fluid 
filtered,  and  the  strychnine  extracted  from  the  filtrate  by  means 
of  ammonia  and  chloroform,  as  already  described.  The  oper- 
ation is  repeated  until  the  residue  obtained  by  evaporating 
the  chloroform  is  no  longer  affected  by  the  treatment  with  sul- 
phuric acid. 

PROLLIUS'S    METHOD. 

The  suspected  substances  are  boiled  with  aqueous  alcohol, 
mixed  with  tartaric  acid,  and  evaporated  at  a  gentle  heat.  The 
remaining  aqueous  solution  is  then  passed  through  a  moisten- 
ed filter,  ammonia  added  to  the  filtrate,  and  the  mixture  shaken 
with  chloroform.  The  chloroform  is  separated,  the  last  trace 
of  the  original  solution  removed  by  washing  with  water,  three 
parts  of  alcohol  added,  and  the  fluid  evaporated.  If  strych- 
nine be  present,  it  will  now  separate  out  in  crystals.  This 
method  is  applicable  only  in  presence  of  a  considerable  quan- 
tity of  strychnine,  and  is  less  serviceable  than  the  one  preced- 
ing. 


DETECTION  OF  ALKALOIDS.  73 

GRAHAM  AND  HOFMAN'S  METHOD. 

This  method,  which  is  applied  to  the  detection  of  strychnine 
in  beer,  is  founded  upon  the  fact  that  an  aqueous  solution  of  a 
strychnine  salt  yields  the  alkaloid  to  animal  charcoal,  from 
which  it  can  be  subsequently  extracted  by  boiling  with 
alcohol.  The  beer  to  be  examined  is  shaken  with  30  grammes 
of  animal  charcoal,  and  the  mixture  then  allowed  to  stand 
twenty-four  hours,  with  occasional  shaking.  The  solution  is 
next  filtered,  the  animal  charcoal  washed  with  water,  and 
boiled  for  half-an-hour  with  four  times  its  weight  of  90  per 
cent,  alcohol.  The  apparatus  represented  in  Fig.  12  is  employed, 
in  order  to  avoid  a  loss  of  substance  in  this  operation. 


Fig.  12. 

The  alcohol  is  filtered  hot,  evaporated,   and  the  residue 
obtained  treated  with  a  small  quantity  of  solution  of  potassa, 

4 


74 


LEGAL   CHEMISTRY. 


and  then  agitated  with  ether.  Upon  spontaneous  evaporation, 
the  ethereal  solution  leaves  the  strychnine  present  in  a  com- 
paratively pure  state. 

Macadam  proposes  to  use  this  process  for  the  detection  of 
strychnine  in  animal  bodies.  For  this  purpose,  the  suspected 
materials  are  heated  with  a  solution  of  oxalic  acid,  as  in  Stas's 
method,  and  the  strychnine  detected  in  the  filtered  solution  in 
the  manner  just  described.  This  method  is  scarcely  to  be  re- 
commended :  the  use  of  animal  charcoal  is  doubtless  serviceable 
in  the  examination  of  beer,  as  it  effects  the  separation  of  a  small 
amount  of  strychnine  from  a  large  quantity  of  fluid,  but  its 
application  to  other  researches  is  much  less  to  be  advised. 

APPLICATION   OF   DIALYSIS    IN   THE   DETECTION   OF   ALKALOIDS. 

In  order  to  apply  the  dialytic  method  to  the  separation  of 
alkaloids,  the  suspected  substances  are  heated  with  hydrochlo- 
ric acid,  and  the  solution  introduced  into  the  dialyzer.  The 
hydrochlorates  of  the  alkaloids,  being  crystalline  bodies, 
transverse  the  membrane,  and  are  contained,  for  the  greater 
part,  after  twenty-four  hours,  in  the  outer  solution.  The 
fluid  is  then  concentrated,  and  the  alkaloids  either  directly 
precipitated,  or  purified  by  one  of  the  preceding  methods. 

IDENTIFICATION    OF    TIIK    ALKALOID. 

The  alkaloid  having  been  isolated  by  one  of  the  preced- 
ing methods,  it  remains  to  establish  its  identity.  Owing  to 
the  small  number  of  reactions  characteristic  of  organic  com- 
pounds, this  is  a  matter  of  considerable  difficulty.  There 
are  two  cases  possible  :  the  alkaloid  may  either  be  volatile  or 
fixed. 


DETECTION  OF  ALKALOIDS. 

THE  ALKALOID  IS  VOLATILE. 


75 


In  this  case  it  may  consist  of  nicotine,  conine  or  aniline  : 
less  known  alkaloids  (piccoline,  etc.)  may  also  be  present. 
We  will  confine  ourselves  to  the  consideration  of  the  three  first 
mentioned. 

The  alkaloid  is  divided  into  several  portions  which  are 
placed  on  watch-glasses  and  submitted  to  the  following  tests  : 

a.  A  drop  is  treated  with  nitric  acid  :  this  may, 
or  may  not,  impart  a  red  tint  to  the  alkaloid  ;  if 
it  does,  another  drop  is  treated  with  dry  hydroch- 
loric acid  gas  :  if  it  assumes  a  deep  violet  color, 

it  probably  consists  of  conine. 

b.  In   case  a   red   color  was  not   produced 
by  the  addition  of   nitric   acid,  another   drop  is 
treated  with  chloride  of  lime.     If  it  acquires  a 
violet  tint,  and  two   other  drops,  when  heated, 
one   with    arsenic  acid,  the  other  with  nitrate 
of  mercury,  become  red,  the  body  present  consists 

of  aniline. 

or  an  homologous  base. 

c.  Should  the  above  tests  fail  to  give  posi- 
tive results,   and  the  substance,   when  treated 
with  chlorine,  assumes  a  blood-red  color,  and 
with  hydrochloric  acid  does  not  change  in  the 
cold  but  turns  to  a  deep  violet  color  upon  boil- 
ing, it  probably  consists  of  nicotine. 

THE  ALKALOID  IS  FIXED. 


A  very  minute  quantity  is  dissolved  in  the  smallest  possi- 
ble amount  of  hydrochloric  acid,  and  an  excess  of  ammonia 


7 6  LEGAL  CHEMISTRY. 

added.  Three  cases  are  now  possible  :  (a)  A  precipitate,  in- 
soluble in  an  excess  of  the  precipitant,  is  immediately  formed  ; 
(&)  a  precipitate  is  formed,  which,  at  first  dissolves,  but  is 
subsequently  deposited  from  the  fluid  ;  (f)  no  precipitate  is 
produced,  or,  in  case  one  forms,  it  dissolves  in  an  excess  of 
the  precipitant  and  fails  to  separate  out  upon  allowing  the  fluid 
to  stand. 

a.  Ammonia  produces  a  permanent  precipitate. 

A  small  quantity  of  an  aqueous  solution  of  carbonic  acid 
is  poured  over  the  alkaloid  in  the  water-glass,  and  notice  taken 
whether  it  dissolves  or  not :  in  either  case  the  mixture  is  eva- 
porated on  a  water-bath  to  dryness,  in  order  to  avoid  a  loss  of 
substance. 

CARBONIC   ACID   FAILS   TO   DISSOLVE   THE   ALKALOID. 

After  the  evaporation  is  completed,  ether  is  added  to  the 
watch-glass  :  the  alkaloid  may,  or  may  not,  be  dissolved.  The 
ether  is  then  evaporated  at  the  ordinary  temperature  of  the 
air. 

Ether  fails  to  dissolve  the  alkaloid. 

It  probably  consists  of  berberine. 

In  this  case,  it  will  possess  a  yellow  color, 
and  its  hydrochlorate  will  give  a  reddish-brown 
precipitate  upon  addition  of  sulphide  of  ammo- 
nia. 

Ether  dissolves  the  alkaloid. — A  small  por- 
tion is  treated  with  nitric  acid.  If  an  intense 
green  coloration  is  produced,  the  remaining  por- 
tion is  dissolved  in  ether,  and  an  ethereal  solu- 
tion of  oxalic  acid  added.  If  the  precipitate 


DETECTION  OF  ALKALOIDS. 


77 


now  formed  does  not  dissolve  upon  the  addition 
of  a  little  water,  there  is  reason  to  suppose  the 
presence  of  aricine. 

Provided  the  addition  of  nitric  acid  did  not 
produce  a  coloration,  the  mixture  of  the  alkaloid 
and  this  acid  is  treated  with  a  small  quantity  of 
sulphuric  acid :  if  the  fluid  now  acquires  a  red 
color,  the  substance  probably  consists  of  narcotine. 

Should  both  nitric  and  sulphuric  acids  fail 
to  cause  a  reaction,  the  alkaloid  is  dissolved  in 
ether,  precipitated  by  an  ethereal  solution 
of  oxalic  acid,  and  the  precipitate  treated  with  a 
little  water.  If  it  dissolves,  it  probably  consists  of  papaverine. 

CARBONIC  ACID  DISSOLVES  THE  ALKALOID. 

The  substance  is  treated  with  ether,  notice  being  taken  if 
it  dissolves,  which  is  evaporated  at  the  ordinary  temperature 
of  the  air  so  as  to  prevent  a  loss  of  minute  portions  of  the 
alkaloid. 

Ether  dissolves  the  alkaloid. — If  nitric  acid 
gives  first  a  scarlet,  then  a  yellow  color,  sul- 
phuric acid  a  yellow,  changing  to  red  and  violet, 
and  hydrochloric  acid  a  violet  color,  the  alkaloid 
present  is  probably  veratrine. 

If  the  above  colorations  are  not  produced, 
chlorine  water  is  added  to  another  portion  of 
the  substance,  then  ammonia  ;  the  formation  of 
a  green  color,  changing  to  violet  and  turning 
red  upon  a  renewed  addition  of  chlorine  water, 
denotes  the  presence  of  quinine. 

In  case  all  of  these  tests  give  but  negative 
results,  and  the  alkaloid  is  soluble  in  concentra- 
ted sulphuric  acid,  a  solution  being  formed  which 


78  LEGAL    CHEMISTRY. 

assumes  a  reddish-violet  tint  when  stirred  with 

a  glass  rod  previously  dipped  in  bromine  water, 

the  presence  of  delphinc. 

is  indicated. 

Ether  fails  to  dissolve  the  alkaloid. — If  the 
substance  is  capable  of  being  sublimed,  *  it  con- 
sists of  cinchonine. 

b.  Ammonia  produces  a  precipitate,  which  redissolves  in  an  excess 
of  the  precipitant,  but  separates  out  after  the  lapse  of  an  hour. 

The  substance  is  treated  with  cold  absolute 
alcohol  and  its  solubility  in  this  menstruum  noted. 
If  it  readily  dissolves,  it  probably  consists  of  brucine. 

The  presence  of  this  alkaloid  is  confirmed  by 
applying  the  following  tests  :  (i)  Nitric  acid  im- 
parts a  blood-red  color  to  the  substance  ;  (2) 
if  treated  with  sulphuric  acid,  it  acquires  a  red- 
dish tint  which  subsequently  changes  to  yellow 
and  green  ;  (3)  chlorine  at  first  fails  to  cause  a 
coloration,  but  after  some  time  a  yellow  color 
which  afterwards  changes  to  a  red  is  produced; 
(4)  upon  treating  the  substance  with  bromine, 
it  immediately  assumes  a  violet  tinge. 

In  case  the  alkaloid  is  only  slightly  soluble  in 
•alcohol,  there  is  reason  to  infer  the  presence  of  strychnine. 

The  following  confirmatory  tests  should  be 
applied  :  (i)  If  the  substance  is  treated  with  a 
mixture  of  sulphuric  acid  and  an  oxydizing  body, 
such  as  bichromate  of  potassa,  binoxide  of 
manganese,,  or  peroxide  of  lead  it  acquires  a 

*  Cinchonine,  when  sublimed,  condenses  in  minute  brilliant  needles. 
—  Trans. 


DETECTION  OF  ALKALOIDS.  79 

violet  color,  which  changes  into  red  and  finally 
passes  into  a  clear  yellow ;  (2)  the  addition  of 
bichloride  of  platinum  produces  a  precipitation 
of  the  hydrochlorate. 

Should,  however,  the  substance  be  only  slight- 
ly soluble  in  alcohol,  and  the  above  reactions 
fail  to  take  place,  the  presence  of  solanine. 

is  indicated.  In  presence  of  this  alkaloid  the 
following  reactions  will  occur  :  (i)  Upon  treating 
the  substance  with  concentrated  sulphuric  acid, 
it  assumes  a  rose  tint,  which  changes  after  some 
time  has  elapsed  first  to  a  deep  violet,  then  to 
a  brown  color ;  (2)  a  solution  of  a  salt  of  the 
alkaloid  reduces  gold  and  silver  salts  ;  (3)  the 
addition  of  oxalic  acid  produces  a  precipitate  in 
the  aqueous  and  even  acid  solution  of  its 
salts. 

c.  Ammonia  fails  to  produce  a  precipitate,  or 
redis  solves  permanently  the  one  formed. 

The  solubility  of  the  alkaloid  in  ether  is  as- 
certained. If  it  be  soluble,  it  may  consist  of 
aconitine,  atropine  or  codeine  ;  if  insoluble,  of 
emetine  or  morphine. 

77/6'  alkaloid  is  soluble  in  ether. — If  bichloride 
of  platinum  fails  to  precipitate  the  hydrochlorate 
from  a  neutral  solution  of  the  alkaloid,  and  sul- 
phuric acid  causes  it  to  assume  a  yellow  color 
which  subsequently  changes  to  a  reddish-violet, 
it  probably  consists  of  aconitine. 

In  case  bichloride  of  platinum  causes  a  pre- 


8o 


LEGAL   CHEMISTRY. 


cipitate  and  sulphuric  acid  fails  to  produce  the 
yellow  coloration  referred  to  above,  the  presence 
of  either  atropine  or  codeine  is  indicated.  In 
order  to  decide  which  of  these  bases  is  present, 
the  substance  is  dissolved  in  pure  chloric  acid 
and  the  solution  allowed  to  spontaneously  evap- 
orate. If  the  alkaloid  is  deposited  during  this 
operation,  it  probably  consists  of 

If  this  is  not  the  case,  there  is  reason  to  infer 
the  presence  of 

The  alkaloid  is  insoluble  in  ether. — If  it  dis- 
solves in  acetone  it  probably  consists  of 

If  acetone  fails  to  dissolve  it,  the  presence  of 
is  indicated. 

The  following  confirmatory  tests  should  be 
applied :  (i)  Upon  treating  the  substance  with 
nitric  acid,  it  acquires  a  blood-red  color  ;  (2)  the 
addition  of  a  solution  of  a  persalt  of  iron  pro- 
duces an  evanescent  blue  coloration  ;  (3)  chlo- 
ride of  gold  is  colored  blue,  when  treated  with 
the  alkaloid  ;  (4)  the  substance  reduces  iodic 
acid :  this  reduction  is  detected  by  adding  to 
the  acid  a  little  starch-paste,  which  turns  blue 
upon  the  liberation  of  the  iodine  ;  (5)  permanga- 
nate of  potassa,  if  heated  with  the  substance,  is 
reduced  and  acquires  a  green  color. 


atropine. 
codeine. 

emetine. 

morphine. 


IDENTIFICATION  OF  DIGITALINE,  PICROTOXINE  AND  COLCHICINE. 

It  has  already  been  remarked  that  in  exhausting  the  first 
acid  solution  with  ether — previous  to  the  neutralization,  ac- 


DE TECTION  OF  ALKALOIDS.  8 1 

cording  to  Otto's  method — colchicine,  a  weak  alkaloid,  digita- 
line,  an  indefinite  mixture,  picrotoxine  (which  appears  to  possess 
the  properties  of  an  acid),  and  traces  of  atropine,  pass  into 
solution. 

The  ether  is  evaporated  on  a  water-bath  to  dryness,  the 
residuary  mass  treated  with  slightly  warmed  water  and  the 
solution  filtered  from  the  undissolved  resinous  matter.  The 
aqueous  solution  is  next  rendered  feebly  alkaline  by  addition 
of  soda  lye,  and  then  well  agitated  with  ether,  until  this  fluid 
ceases  to  leave  a  residue  upon  evaporation.  The  ethereal  so- 
lution is  now  decanted,  and  the  water  present  removed  by 
means  of  chloride  of  calcium.  If  it  is  evaporated,  a  residue 
containing  the  colchicim,  digitaline  and  traces  of  atropine 
(mixed  possibly  with  a  minute  quantity  of  picrotoxine,  which  is 
here  left  out  of  consideration)  is  obtained. 

a.  The  alkaline  solution,  from  which  the  ether  has  been  re- 
moved, is  acidulated  with  hydrochloric  acid  and  again  shaken 
with  ether.  The  picrotoxine  present  is  now  dissolved,  and 
upon  dehydrating  (by  means  of  fused  chloride  of  sodium) 
and  evaporating  the  ethereal  solution  can  be  obtained  in 
crystals.  The  crystals  of  picrotoxine  are  easily  recognized 
by  their  forming  in  feathery  tufts  as  well  as  by  their  length 
and  silky  brilliancy.  Should  crystals  fail  to  form  in  a  short 
time,  it  is  advisable  to  take  up  the  residue,  left  by  the  evapo- 
rations of  the  ether,  with  slightly  warmed  alcohol,  and  to  allow 
the  latter  to  spontaneously  evaporate  on  a  watch-glass,  or,  if 
the  quantity  of  substance  is  exceedingly  minute,  on  the  slide 
of  a  microscope.  After  determining  the  form  of  the  crystals, 
it  should  be  ascertained  that  they  possess  an  intense  bitter 
taste  and  exhibit  the  other  characteristic  properties  of  picrotox- 
ine. The  following  reaction  is  distinctive  :  If  the  crystals 
are  dissolved  in  an  aqueous  solution  of  soda  and  a  few  drops 

4* 


82  LEGAL  CHEMISTRY. 

of  "  Fehling's  solution  "*  added,  a  reddish  precipitate  of  cu- 
prous oxide  is  formed. 

b.  Provided  picrotoxine  has  not  been  found,  the  ethereal  so- 
lution obtained  by  agitating  the  alkaline  fluid  with  ether  is  to 
be  examined  for  colchicine  and  digitaline.  To  this  end,  the 
residue  obtained  upon  evaporating  the  solution  to  dryness  is 
taken  up  with  water,  and  the  filtered  fluid  tested  as  follows  • 
i.  It  is  ascertained  if  a  drop  of  the  solution  possesses  the 
bitter  taste  of  digitaline.  2.  Another  drop  is  treated  with  so- 
lution of  tannin  ;  if  either  alkaloid  be  present,  a  precipitate  is 
formed.  3.  Two  drops  of  the  solution  are  next  tested  :  one 
with  tincture  of  iodine,  the  other  with  chloride  of  gold.  These 
reagents  precipitate  colchicine,  but  do  not  affect  solutions  of 
digitaline  or  picrotoxine.  Unfortunately  traces  of  atropine,  pos- 
sibly present,  would  cause  the  same  reaction  ;  the  test  there- 
fore fails  to  be  conclusive.  4.  Several  portions  of  the  solution 
are  evaporated  on  watch  crystals.  Concentrated  nitric  acid  is 
added  to  one  portion  :  if  colchicine  be  present,  an  evanescent 
violet  coloration  is  produced,  which  changes  to  a  light  yellow 
upon  addition  of  water,  and  to  a  pure  yellow  or  reddish-orange 
color,  if  the  mixture  is  saturated  with  a  slight  excess  of  caustic 
alkali.  5.  Another  portion  of  the  residue  is  dissolved  in  a  few 
drops  of  concentrated  sulphuric  acid,and  the  solution  stirred  with 
a  glass  rod  moistened  with  bromine  water  :  in  presence  of  digit- 
aline a  violet-red  color  is  produced.  This  coloration  is  more  dis- 
tinct when  a  small  quantity  of  the  alkaloid  and  an  excess  of  sul- 
phuric acid  are  present.  6.  If  a  large  amount  of  substance  is  at 
hand,  the  residue  can  be  boiled  with  hydrochloric  acid,  and  the 
green  or  brownish  color  and  characteristic  odor  of  digitaline  pro- 

*  An  alkaline  solution  of  tartrate  of  coppe*,  employed  in  the  examina- 
tion of  sugar,  urine,  and  wine. —  Trans. 


DETECTION  OF  ALKALOIDS.  83 

duced,  in  case  this  body  be  present :  this,  however,  is  not  a  very 
delicate  test.  7.  Finally;  it  is  advisable  when  the  presence  of  dig- 
italine  is  suspected  to  ascertain  its  physiological  action.  For  this 
purpose,  a  minute  quantity  of  the  substance  is  placed  upon  the 
heart  of  a  frog  :  in  presence  of  the  alkaloid,  the  pulsations  are 
immediately  retarded,  or  even  arrested. 

Although  by  means  of  the  tests  given  above  the  existence 
of  a  special  alkaloid,  or  of  one  of  the  ill-defined  substances  just 
mentioned,  may  be  justly  regarded  as  probable,  its  presence  has 
not  yet  with  certainty  been  demonstrated.  This  is  especially 
true  in  cases  where  the  compound  possesses  but  few  character- 
istic properties.  When  possible,  the  suspected  substance  should 
be  obtained  in  a  crystaline  form,  and  then  compared  by  aid  of  the 
microscope — if  the  small  quantity  present  permits  of  no  other  ex- 
amination— with  crystals  of  the  pure  alkaloid,  prepared  under 
the  same  conditions. 

In  case  20  or  evsn  10  centigrammes  of  substance  are  at  hand, 
it  is  best  to  convert  the  alkaloid  into  its  hydrochlorate,  and 
evaporate  the  solution  of  this  salt  to  dryness.  The  residue, 
after  being  weighed,  is  dissolved  in  water,  and  a  solution  of  sul- 
phate of  silver  added.  The  precipitate  of  chloride  of  silver 
formed  is  collected  and  carefully  weighed,  in  order  to  calculate 
the  weight  of  the  chlorine  contained  in  the  hydrochlorate  and 
consequently  the  molecular  weight  of  the  alkaloid.  The  filtrate 
from  the  chloride  of  silver,  which  contains  the  alkaloid  in  the 
state  of  sulphate,  is  treated  with  hydrochloric  acid,  to  remove 
the  excess  of  silver  present  and  the  fluid  then  filtered.  The  fil- 
trate is  next  shaken  with  potassaand  ether.  Upon  decanting  and 
evaporating  the  ethereal  solution,  a  residue  consisting  of  the 
alkaloid  present  is  obtained,  which  is  then  purified  by  crystal- 
lization from  alcohol.  An  elementary  analysis  of  the  alkaloid 


84  LEGAL  CHEMISTRY. 

is  now  executed.  Certainty  as  to  the  presence  of  an  individ- 
ual alkaloid  is  attainable  only  when  the  execution  of  this  con- 
firmatory test  is  possible.  The  reactions  previously  described  can 
be  performed  with  fifteen  centigrammes  of  substance,  and  this 
amount  is  sometimes  contained  in  a  cadaver.  If  but  one  or 
two  centigrammes  are  at  hand,  it  is  still  possible  to  detect  the 
presence  of  an  alkaloid  ;  a  conclusion,  however,  as  to  which  can- 
not be  arrived  at,  especially  if  the  substance  found  is  a  liquid 
or  an  amorphous  body,  and  one  that  presents  few  distinctive 
properties. 


III. 


METHODS  TO  BE  EHPI,O  VE  D,  WHEIV  1VO  CtE W  TO  THE 
NATURE  OF  THE  POISON  PRESENT  CAN   LIE 
OBTAINED. 


IF  poisoning  has  been  caused  by  the  administration  of  a 
mixture  of  numerous  substances  and  these  greatly  differ  in 
their  properties,  it  is  impossible  to  demonstrate  in  an  incon- 
testible  manner  the  presence  of  each  individual  poison.  This 
contingency  fortunately  but  seldom  arises  ;  the  criminal  usual- 
ly has  recourse  to  one  or  two  poisons,  the  detection  of  which  is 
possible.  It  must  not  be  imagined,  however,  that  the  presence 
of  a  poison  in  an  organ  can  at  once  be  detected  with  certainty 
by  the  mere  application  of  a  few  tests  ;  because,  in  searching  for 
a  substance  which  is  absent,  we  may  unwittingly  destroy  the  one 
present,  or,  at  least,  transform  it  into  combinations  which  would 
not  allow  of  a  definite  conclusion  as  to  its  original  condition. 

In  order  to  follow  a  systematic  method  in  researches  of 
this  nature,  it  is  advisable  to  divide  the  materials  under  exam- 
ination into  three  parts  :  one  portion  is  preserved,  in  order  to 
ascertain  its  physiological  effects  on  animals,  the  chemical  anal- 
sis  having  failed  to  give  positive  results.  The  other  portions 
are  submitted  to  analysis,  but  with  slightly  different  objects 


86  LEGAL   CHEMISTRY. 

in  view  ;  one  is  subjected  to  a  series  of  tests  which  are  adapt- 
ed, under  all  circumstances,  to  place  the  chemist  on  the  track 
of  the  poison  present,  and  which,  in  some  cases,  may  even  give 
conclusive  and  definite  results.  Should  these  tests  furnish  only 
indications  of  the  nature  of  the  poison,  the  remaining  portion 
serves,  with  the  assistance  of  this  information,  to  establish 
beyond  doubt  the  identity  of  the  substance. 

INDICATIVE    TESTS. 

Two  cases  may  present  themselves :  the  materials  to  be 
examined  possess  either  an  alkaline  (or  neutral)  or  an  acid 
reaction.  As  the  methods  to  be  pursued  in  either  of  these 
cases  differ  somewhat,  they  will  be  treated  separately. 

THE   SUBSTANCE    POSSESSES   AN   ACID   REACTION. 

The  materials  are  mixed  with  water,  placed  in  a  retort 
provided  with  a  delivery-tube  which  dips  in  a  solution  of 
nitrate  of  silver,  and  heated  over  a  water-bath :  if  a  cyanide 
be  present,  hydrocyanic  acid  will  be  disengaged,  and  a  white 
precipitate  of  cyanide  of  silver  formed  :  this  is  examined  as 
previously  directed  (vide  p.  50). 

In  case  a  precipitate  is  not  produced  by  the  above  treat- 
ment, more  water  is  added  to  the  retort,  and  the  mixture 
boiled  for  about  an  hour,  care  being  taken  to  collect  the 
evolved  vapors  in  a  well-cooled  receiver.  The  portion  remain- 
ing in  the  retort  is  thrown  on  a  filter  and  the  filtrate  obtained 
united  with  the  distillate.  The  residue  remaining  on  the 
filter  is  next  washed  with  boiling  absolute  alcohol,  the 
washings  being  added  to  the  aqueous  solution.  In  this  way, 
the  suspected  substances  are  divided  into  soluble  and  insolu- 


INDICATIVE  TESTS.  87 

ble    portions,    which   are   examined   separate!)',   as  directed 
below. 

a.    LIQUID    PORTION. 

If  the  addition  of  alcohol  caused  a  precipitation  of  animal 
matters,  these  are  separated  by  filtering  the  solution.  The 
filtrate  is  then  placed  under  a  bell-jar  over  concentrated 
sulphuric  acid  until  its  volume  is  considerably  reduced.  The 
solution  may  contain  organic  and  inorganic  bases  and  acids. 
In  order  to  detect  all  bodies  that  are  present,  the  following 
course  is  pursued  : 

(i).  A  current  of  sulphuretted  hydrogen  is  conducted 
through  the  solution :  the  precipitation  of  some  metals, 
usually  thrown  down  by  this  gas,  may  fail  to  take 
place  in  this  instance,  owing  to  the  presence  of  organic 
substances  ;  however,  some  metals  are  precipitated,  even  in 
presence  of  organic  compounds,  and  organic  acids  are  but 
seldom  present.  In  case  a  precipitate  is  formed,  it  is  mixed 
with  pure  silica,  collected  on  a  filter,  and  treated  with  nitric 
acid.  If  the  precipitate  fails  to  dissolve,  it  is  treated  with 
aqua  rcgia.  In  either  case,  the  solution  obtained  is  examined 
for  metals  by  the  ordinary  methods. 

(2).  The  solution  in  which  sulphuretted  hydrogen  failed  to 
produce  a  precipitate,  or  the  filtrate  separated  from  the  pre- 
cipitate formed,  is  divided  into  two  parts :  one  portion  is 
treated  with  ether  and  a  solution  of  potassa ;  the  other  with 
ether  and  a  solution  of  soda.  Both  mixtures  are  then  well 
agitated,  and  notice  taken  if  the  ether  dissolves  any  thing:  if 
so,  the  operation  is  repeated  several  times  until  all  soluble 
substances  are  removed.  The  ethereal  solutions  are  next 
decanted  and  united,  and  then  submitted  to  the  examination 
for  alkaloids  as  directed  pp.  65-84. 


88  LEGAL   CHEMISTRY. 

(3).  If — the  above  treatment  giving  either  positive  or 
negative  results — a  precipitate  insoluble  in  ether  is  formed 
by  the  addition  of  potassa  or  soda,  it  is  collected  on  a  filter, 
washed,  and  dissolved  in  an  acid.  The  solution  is  then  tested 
for  mineral  bases. 

(4).  In  case  no  definite  result  has  been  obtained  by  the 
preceding  operations,  one  of  the  portions  (for  instance,  the 
one  to  which  potassa  was  added)  is  tested  for  the  acids  possi- 
bly present  in  the  state  of  salts.  The  solution  is  divided  into 
two  parts  (A  and  B)  which  are  examined  separately : 

PORTION  A. — This  is  evaporated  to  clryness  and  the  residue 
divided  into  four  parts  which  are  then  tested  for  hydrofluoric, 
nitric,  oxalic,  and  acetic  and  formic  acids. 

a.  HYDROFLUORIC  ACID. — A  portion  of  the  residue  is  heated 
in  a  platinum  crucible  with  sulphuric  acid,  and  the  crucible 
covered  with  the  convex  face  of  a  watch-crystal   coated  with 
wax  in  which  lines  have  been  traced  with  a  pointed  piece  of 
wood.      If,  after  gently  heating  the  crucible  for  some  time 
and  removing  the  watch-crystal,  the  lines  traced  in  the  wax 
are  found  to  be  etched  in  the  glass,  the  substance   under  ex- 
amination contains  a  fluoride. 

b.  NITRIC  ACID. — If  this  acid  be  present,   and  a  second 
portion  of  the  residue  is  heated  with  sulphuric  acid  and  cop- 
per, reddish-fumes  are  evolved.    Upon  conducting  the  vapors 
into  a  solution  of  sulphate  of  iron  or  narcotine,  the   reactions 
already  mentioned  in  treating  of  nitric  acid  take  place. 

c.  OXALIC  ACID. — The  third  portion  of  the  residue  is  heated 
with  sulphuric  acid,  and  the  evolved  gas  carefully  collected.  It 
should  then  be  confirmed  by  an  elementary  analysis  that  the 
gas  consists  of  equal  volumes  of  carbonic  oxide  and  carbonic 
acid.     This  test  is   not   conclusive  ;  it  is   also   necessary  to 
ascertain  if   the   precipitate   produced  by  the   addition  of  a 


INDICATIVE    TESTS.  89 

baryta  solution  (vide:  under  portion  .Z?.)  produces  the  same 
reaction,  inasmuch  as  other  organic  bodies  could  give  -rise  to 
carbonic  oxide  and  carbonic  acid,  and  the  danger  of  both 
admitting  the  presence  of  oxalic  acid,  when  it  is  absent, 
and  omitting  its  detection,  in  case  it  is  present,  would  be 
incurred. 

4  ACETIC  AND  FORMIC  ACIDS. — The  fourth  portion  of 
the  residue  is  distilled  with  dilute  sulphuric  acid.  After 
determining  that  a  small  portion,  previously  neutralized  with 
a  base,  acquires  a  red  color,  upon  addition  of  a  solution  of  a 
persalt  of  iron,  the  distillate  is  divided  into  two  parts.  One 
portion  is  treated  with  bichloride  of  mercury  :  if  formic  acid 
be  present,  metallic  mercury  is  formed,  with  evolution  of  car- 
bonic acid  which  produces  turbidity  in  lime-water.  The 
remaining  portion  of  the  fluid  is  digested,  in  the  cold,  with  an 
excess  of  litharge  :  in  presence  of  acetic  acid,  a  soluble  basic 
salt  of  lead,  possessing  an  alkaline  reaction,  is  produced. 

PORTION  B. — The  second  portion  of  the  solution  is  super- 
saturated with  nitric  acid,  and  this  neutralized  by  addition  of 
a  slight  excess  of  ammonia.  The  ammonia  is  then  expelled 
by  boiling  the  fluid,  and  a  solution  of  nitrate  of  baryta  added. 
If  a  precipitate  forms,  it  is  collected  and  subsequently  examined 
for  sulphuric,  phosphoric,  oxalic  and  boric  acids  as  directed 
below.  rT\[&  filtrate  is  preserved  and  tested  for  hydrochloric, 
hydrobromic  and  hydriodic  acids. 

a.  OXALIC  ACID. — A  portion  of  the  precipitate  produced 
by  the  addition  of  nitrate  of  baryta  is  submitted  to  the  test 
mentioned  under  the  treatment  of  portion  A. 

6.  SULPHURIC  ACID. — If  an  insoluble  residue  remains 
upon  treating  the  remainder  of  the  precipitate  with  dilute 
hydrochloric  acid,  it  consists  of  sulphate  of  baryta  and  indi- 
cates the  presence  of  sulphuric  acid. 


9o  LEGAL  CHEMISTRY. 

c.  PHOSPHORIC  ACID. — An  excess  of  solution  of  alum  and 
ammonia  is  added  to  the  portion  of  the  precipitate  dissolved 
in  hydrochloric  acid.     If  phosphoric  acid  be  present,  insoluble 
phosphate  of  alumina  is  precipitated.     This  is  brought  upon 
a  filter .-  ti\z  filtrate  being  preserved  and  subsequently  examined 
for  boric  acid.     Upon  boiling  the  precipitate  with  solution  of 
silicate  of  potassa,  silicate  of  alumina  is  thrown  down,  and 
phosphate  of  potassa  remains  in  solution.     Chloride  of  am- 
monia is  now  added  to  the  liquid — in  order  to  eliminate  the 
excess  of  silica  from   the  silicate — and  the  solution  filtered. 
T\\o.jiZtratj  is  then  tested  for  phosphates,  by  means  of  molyb- 
date  of  ammonia  (vide :  detection  of  phosphoric  arid,  p.  48). 

d.  BORIC    ACID. — The    filtrate    from    the    precipitate    of 
phosphate  of  alumina  is   evaporated  to  dryness,  the  residue 
mixed  with  sulphuric  acid  and  alcohol,  and  the  latter  ignited. 
If  the  substance  contains  boric  acid,  the  alcohol  will  burn  with 
a  green  flame. 

The  filtrate,  separated  from  the  precipitate  produced  by 
the  addition  of  nitrate  of  baryta,  may  contain  hydrochloric, 
hydrobromic  and  hydriodic  acids.  In  order  to  detect  these 
compounds,  some  nitrate  of  silver  is  added  to  the  solution,  and 
the  precipitate  that  may  form  carefully  washed  and  decom- 
posed by  fusion  with  potassa.  The  mass  is  then  dissolved  in 
water,  and  the  solution  submitted  to  the  following  tests  : 

e.  HYDRIODIC  ACID. — Some  starch  paste  and  nitric  acid- 
containing  nitrous  acid  in  solution — are  added  to  a  portion  of 
the  solution :  in  presence  of  an  iodide,  the  fluid  immediatel 
acquires  a  blue  color. 

f.  HYDROBROMIC    ACID. — In    case   iodine    has  not  been 
detected,   chlorine  water  and  ether  are  added  to  a  second 
portion  of  the  fluid,  and  the  mixture  well  agitated.     If  bromine 
be  present,  the  ether  will  assume  a  brown  color.     In  case 


INDICATIVE   TESTS.  9! 

iodine  is  also  contained  in  the  fluid,  and  the  detection  of 
bromine  is  desired,  it  is  necessary  to  acidulate  the  solution 
with  hydrochloric  acid,  and  then  shake  it  with  chloride  of 
lime  and  bisulphide  of  carbon.  The  bisulphide  of  carbon 
dissolves  the  iodine,  acquiring  a  violet  color,  which  disappears 
upon  a  renewed  addition  of  chloride  of  lime  ;  whereas,  in 
presence  of  bromine  an  orange  coloration  remains,  even  after 
the  disappearance  of  the  iodine  reaction. 

£-.  HYDROCHLORIC  ACID. — Since  the  substance  under  ex- 
amination will  already  contain  hydrochloric  acid,  it  is  unneces- 
sary, in  most  cases,  to  institute  a  search  for  this  compound. 
Nevertheless,  it  may  be  well  to  take  a  quantity  of  the  solution, 
corresponding  to  a  known  weight  of  the  original  substance, 
and  precipitate  the  acid  by  adding  nitrate  of  silver.  The 
precipitate  formed  is  dried  and  weighed.  It  is  then  heated 
in  a  current  of  chlorine,  in  order  to  completely  convert  it 
into  chloride  of  silver,  and  its  weight  again  determined.  Only 
in  case  the  amount  of  chloride  found  is  very  large,  is  it  to  be 
inferred  that  the  poisoning  has  been  caused  by  hydrochloric 
acid. 

h.  HYDROSULPHURIC  ACID. — (Sulphuretted  hydrogen}.  If 
the  precipitate  produced  by  nitrate  of  silver  possesses  a  black 
color,  it  may  consist  of  a  sulphide.  Upon  treating  a  portion 
with  solution  of  hyposulphite  of  soda,  all  but  the  sulphide  of 
silver  is  dissolved.  In  case  a  residue  remains,  it  is  calcined 
with  nitrate  of  soda,  and  the  sulphate  formed  detected  by 
adding  a  soluble  barium  salt  to  its  solution. 

Sulphates,  chlorides,  carbonates  and  phosphates  are  most 
frequently  met  with  in  the  preceding  examination,  and  it  should 
be  carefully  noticed  which_of  these  salts  exist  in  the  greatest 
abundance.  If  acids  of  comparatively  rare  occurrence  (such  as 
the  oxalic  and  tartaric)  are  found,  their  approximate  amount 


92 


LEGAL  CHEMISTRY. 


is  also  to  be  noted.  These  facts,  together  with  the  original 
acidity  of  the  materials  and  the  absence  of  other  toxical  bodies, 
would  lead  to  the  conclusion  that  the  poisoning  was  caused  by 
the  reception  of  an  acid,  as  well  as  to  the  identification  of  the 
special  acid  used.  In  subsequently  effecting  the  detection  of 
the  poison  by  the  determinative  tests,  the  danger  of  destroying 
other  poisons  possibly  contained  in  the  substance  will  be  ob- 
viated, as  the  question  of  the  absence  or  presence  of  these  latter 
will  have  been  previously  decided. 

(5).  The  examination  for  acids  concluded,  the  various  fluids 
which  have  accumulated,  and  from  which  the  acids  present 
have  been  separated,  are  united  and  the  whole  evaporated  to 
dryness.  The  organic  substances,  present  in  the  residue  ob- 
tained, are  destroyed  by  means  of  nitric  acid,  and  the  residual 
mass  examined  for  soda.  If  this  substance  has  not  been  in- 
troduced into  the  portion  of  fluid  examined,  and  is  discovered 
in  a  quantity  largely  in  excess  of  the  amount  normally  con- 
tained in  the  organism,  it  is  probable  that  poisoning  has  been 
caused  by  its  administration,  and  that  an  acid  has  also  been 
given,  either  in  order  to  mask  the  poison,  or  to  act  as  an  an- 
tidote. In  this  case,  it  is  necessary  to  carefully  search  for 
acetic  acid,  as  this  is  the  substance  usually  employed  as  an 
antidote  for  alkalies. 

(6.)  Whatever  results  have  been  obtained  by  the  preceding 
examinations,  the  portion  of  the  fluid  which  has  been  treated 
with  soda  (vide  p.  87)  is  evaporated  to  dryness.  The  or- 
ganic matters  possibly  present  are  destroyed  by  means  of 
nitric  acid,  or  aqua  regia,  and  the  residue  taken  up  with  water. 
The  solution  so  obtained  is  then  examined  for  metals  (includ- 
ing potassa,  which  salt  has  not  been  introduced  into  this  por- 
tion of  the  fluid  in  any  of  the  preceding  operations)  by  the 
usual  methods. 


INDICATIVE  TESTS.  93 

(7).  The  soluble  portion  of  the  suspected  materials  having 
been  thoroughly  tested,  the  undissolved  substances  remaining 
on  the  filter  are  next  examined. 


5.      SOLID   PORTION. 

(i).  The  organic  matter  present  is  first  destroyed  by  treat- 
ment with  aqua  regia.  The  fluid  is  then  evaporated  to  dryness, 
and  the  residue  heated  until  the  nitric  acid  is  entirely  expelled; 
the  escaping  vapors  being  collected  in  a  cold  receiver.  The 
residue  is  next  taken  up  with  water,  the  solution  filtered,  and 
sulphuric  acid  added.  Should  a  precipitate  of  sulphate  of 
lime,  sulphate  of  baryta  or  sulphate  of  strontia  form,  it  is  sep- 
arated from  the  fluid  and  further  examined.  The  filtered  solu- 
tion is  then  introduced  into  Marsh's  apparatus,  sodium  amal- 
gam being  employed  for  generating  the  hydrogen,  and  tested 
for  arsenic  and  antimony  by  means  of  the  reactions  previously 
given. 

(2).  Whether  one  of  the  above  poisons  be  discovered  or  not, 
the  still  acid  fluid  is  removed  from  the  flask,  a  current  of 
chlorine  conducted  through  it  for  several  hours  and  the  solution 
then  examined  for  mercury  by  Flandin  and  Danger's  method. 
In  case  mercury  is  found  it  could  scarcely  have  originated  from 
the  metal  in  Marsh's  apparatus,  as  this  would  not  be  attacked 
by  cold  dilute  sulphuric  acid  :  however,  to  remove  all  doubts, 
the  test  should  be  repeated  with  a  portion  of  the  substances 
reserved  for  the  examination  by  the  determinative  tests. 

(3).  Whatever  have  been  the  results  of  the  above  examina- 
tions, it  is  still  to  be  ascertained  if  the  fluid,  which  has  been 
successively  treated  by  Marsh's  and  Flandin  and  Danger's 
methods,  does  not  contain  other  metals.  This  is  accomplished 
by  means  of  the  ordinary  reactions. 


94 


LEGAL  CHEMISTRY. 


THE     SUBSTANCE     POSSESSES    A     NEUTRAL     OR     AN     ALKALINE 

REACTION. 

The  examination  is  conducted  in  precisely  the  same  manner 
as  in  the  preceding  case,  excepting  that  the  materials  are  first 
acidulated  with  oxalic  or  tartaric  acids.  Particular  attention 
should  be  given  to  the  search  for  soda,  potassa,  lime,  baryta 
and  strontia,  and  the  determinative  tests  subsequently  applied 
according  to  the  indications  obtained. 

DETERMINATIVE  TESTS. 

In  many  instances  the  tests  we  have  termed  indicative  be- 
come determinative  in  their  character.  This  is  the  case  when 
the  isolation  of  an  alkaloid  or  a  metal  (unless  mercury  be 
found  under  the  circumstances  already  mentioned)  is  accom- 
plished ;  the  results  obtained  are  then  conclusive.  If,  on  the 
other  hand, — not  being  able  to  separate  either  an  alkaloid  or  a 
metal — upon  saturating  the  originally  acid  fluid  with  potassa, 
or  soda,  the  salts  of  these  bases  have  been  found  in  abun- 
dance, there  is  reason  to  infer  that  the  poisoning  has  been 
caused  by  an  acid ;  or,  if,  after  the  neutralization  of  the  origi- 
nally alkaline  solution  with  an  acid,  potassa  or  soda  are  discov- 
ered in  a  large  quantity,  poisoning  by  an  alkali  is  indicated. 

In  case  the  fluid  is  neutral,  but  more  or  less  colored  and 
odoriferous,  and  iodides  or  bromides  are  detected,  we  may 
justly  suspect  that  the  poisoning  has  been  caused  by  the  recep- 
tion of  iodine  or  bromine. 

According  to  the  indications  furnished,  iodine,  bromine, 
one,  or  all  of  the  acids,  the  caustic  alkalies,  etc.,  are  then  de- 
tected by  means  of  the  methods  to  be  employed  in  cases  where 
the  expert  has  a  clew  to  the  poison  present.  In  this  manner, 


DETERMINATIVE  TESTS. 


95 


the  presence  of  potassa  and  soda,  and  of  bromine  and  iodine, 
even  in  mixtures,  is  easily  ascertained.  It  only  remains  to 
mention  the  course  to  be  pursued  when  suspicion  exists  that 
poisoning  has  been  caused  by  the  administration  of  a  mixture 
of  several  acids.  The  suspected  materials  are  boiled  with  water, 
and  alcohol  added  to  the  solution  in  order  to  coagulate  the 
animal  matters.  The  solution  is  next  filtered,  the  filtrate  plac- 
ed in  a  retort  provided  with  a  receiver  and  distilled  until  the 
residual  portion  acquires  a  pasty  consistency.  In  this  way,  the 
acids  present  are  separated  into  two  classes :  (a)  those  that  are 
sufficiently  volatile  to  have  passed  into  the  receiver,  such  as, 
acetic,  nitric,  hydrochloric  and  sulphuric  acids  (the  latter  acid 
will  only  be  partially  volatilized)  ;  and  (/»)  those  that  remain  in 
the  retort.  The  former  are  detected  by  examining  the  distillate 
as  previously  directed. 

The  residue  remaining  in  the  retort  is  treated  with  absolute 
alcohol,  the  fluid  filtered,  and  a  solution  of  acetate  of  lead 
added  to  the  filtrate  :  sulphuric,  phosphoric  and  oxalic  acids, 
if  present,  are  precipitated.  The  precipitate  is  suspended  in 
water  and  decomposed  by  means  of  sulphuretted  hydrogen. 
The  acids  contained  are  now  set  free,  and  are  detected  by  ap- 
plying the  tests  already  mentioned. 

If  there  be  reason  to  suspect  the  presence  of  both  sulphuric 
and  oxalic  acids,  the  distillation  is  discontinued  after  a  short 
time.  The  two  acids  are  dissolved  by  shaking  the  moderately 
concentrated  fluid  remaining  in  the  retort  with  ether,  and, 
upon  evaporating  the  solution,  will  be  obtained  in  a  state  suit- 
able for  examination.  Oxalic  acid  is  then  detected  by  means 
of  sulphate  of  lime  ;  sulphuric  by  means  of  oxalate  of  baryta. 

The  above  examinations  would  fail  to  effect  the  detection, 
of  phosphorus,  and  it  is  necessary  to  examine  a  separate  portion 
of  the  original  substance  for  this  body. 


IV. 

MISCELLANEOUS    EXAMINATIONS. 


DETKR.TII.YATIO.X    OF    THE    NATURE     AND     COLOR   OF 
THE  HAIR  AND  BEARD. 

A  criminal,  in  order  to  conceal  his  identity,  may  change 
the  color  of  the  hair  and  beard  by  artificial  means  ;  either  to 
a  darker  shade,  in  case  they  were  naturally  of  a  light  color, 
or,  to  a  lighter  hue,  if  they  were  originally  dark,  and  the 
chemical  expert  may  be  called  upon  to  detect  this  artificial 
coloration,  and  restore  the  original  color  of  the  hair. 

It  may  also  happen,  that  portions  of  hair  still  adhere  to 
the  clots  of  blood  sometimes  found  on  an  instrument  which 
has  been  employed  in  the  commission  of  a  crime,  and  conse- 
quently the  question  may  arise  as  to  the  nature  of  the  hair, 
whether  it  be  human  or  animal. 

DETERMINATION   OF   THE   COLOR   OF   THE    HAIR   AND   BEARD. 

The  mode  of  examination  necessary  when  the  hair  has 
been  blackened  is  different  from  that  used  when  it  has  been 
decolorized. 


EXAMINATION  OF  HAIR. 


The  hair  has  been  blackened. 


97 


As  various  methods  of  dyeing  hair  black  are  in  use,  the 
means* of  restoring  the  original  color  differ.  The  following 
are  the  methods  most  usually  employed  in  dyeing  : 

i°.  The  hair  is  well  rubbed  with  a  pomade,  in  which  finely 
pulverized  charcoal  is  incorporated.  This  preparation,  which 
is  sold  under  the  name  of  " mela'inocome"  possesses  the  dis- 
advantage of  soiling  the  fingers  and  clothing,  even  for  several 
days  after  its  application. 

2°.  The  hair  is  moistened  with  a  dilute  solution  of  ammonia, 
and  a  perfectly  neutral  solution  of  a  bismuth  salt  (chloride 
or  nitrate)  is  then  applied.  It  is  subsequently  washed,  and  al- 
lowed to  remain  in  contact  with  a  solution  of  sulphuretted 
hydrogen. 

3°.  The  same  operation  is  performed,  a  lead  compound 
being  substituted  for  the  bismuth  salt. 

4°.  A  mixture  of  litharge,  chalk,  and  slacked  lime  is  ap- 
plied, and  the  head  covered  with  a  warm  cloth.  The  hair  is 
afterwards  washed,  first  with  dilute  vinegar,  then  with  the 
yolk  of  an  egg. 

5°.  The  hair  is  first  cleansed  with  the  yolk  of  an  egg,  and 
then  moistened  with  a  solution  of  plumbate  of  lime  ;  or, 

6°.  It  is  moistened  with  a  solution  of  nitrate  of  silver,  to 
which  a  quantity  of  ammonia  sufficient  to  dissolve  the  precipi- 
tate first  formed  has  been  added. 

The  first  method  merely  causes  a  mechanical  admixture  of 
a  coloring  matter  with  the  hair.  In  the  four  succeeding  pro- 
cesses, a  black  metallic  sulphide  is  produced  ;  either  by  the 
subsequent  application  of  a  solution  of  sulphuretted  hydro- 
gen, or  by  the  action  of  the  sulphur  normally  present  in  the 
hair. 

5 


98  LEGAL  CHEMISTRY. 

In  the  last  method,  the  formation  of  sulphide  of  silver 
doubtless  occurs  ;  but  the  principal  change  that  takes  place 
is  probably  due  to  the  action  of  light,  which,  as  is  well  known, 
decomposes  the  salts  of  silver. 

In  order  to  restore  the  original  color  to  hair  which  has 
been  treated  with  "  melariiocome"  it  is  only  necessary  to 
dissolve  in  ether  the  fatty  matters  present,  and  then  remove 
the  charcoal  by  washing  with  water. 

In  case  the  hair  has  been  dyed  by  means  of  a  bismuth  or 
lead  salt  (as  in  methods  2.  3,  4  and  5),  it  is  immersed  for 
several  hours  in  dilute  hydrochloric  acid  :  the  metal  present 
dissolves,  as  chloride,  and  the  original  color  of  the  hair  is 
rendered  apparent.  It  then  remains  to  detect  the  metal 
dissolved  in  the  acid  solution,  in  order  to  establish,  beyond 
doubt,  the  fact  that  a  dye  has  been  employed.  This  is  ac- 
complished by  means  of  the  methods  used  for  the  detection  of 
metals  is  cases  of  supposed  poisoning. 

If,  finally,  an  ammoniacal  solution  of  nitrate  of  silver  has 
been  employed  to  cause  the  coloration,  the  hair  is  immersed, 
for  some  time,  in  a  dilute  solution  of  cyanide  of  potassium,  and 
the  fluid  subsequently  examined  for  silver.  In  case  a  portion 
of  the  salt  has  been  converted  into  the  sulphide,  it  will  be 
difficult  to  restore  the  original  color,  as  the  removal  of  this 
compound  is  not  easily  effected. 

The  hair  has  been  decolorized. 

Black  hair  can  be  bleached  by  means  of  chlorine-water, 
the  various  shades  of  the  blonde  being  produced  by  the  more 
or  less  prolonged  action  of  the  reagent.  In  this  case,  the 
odor  of  chlorine  is  completely  removed  only  with  great 
difficulty,  and  the  hair  is  rarely  uniformly  decolorized. 


EXAMINATION  OF  HAIR.  99 

The  expert  may  therefore  be  able  to  observe  indica- 
tion that  will  greatly  assist  him  in  arriving  at  a  definite  con- 
clusion. The  hair  should  be  carefully  examined  up  to  the 
roots :  if  several  days  have  elapsed  since  the  decolorization 
has  been  performed,  the  lower  portion  of  the  hair  will  have 
grown  and  will  exhibit  its  natural  color.  No  method  has  yet 
been  proposed  that  restores  the  original  color  to  bleached 
hair.  It  is  very  possible,  however,  that  this  end  would  be 
attained  by  allowing  nascent  hydrogen  to  act  upon  the  de- 
colorized hair.  For  this  purpose,  it  would  be  necessary  to 
immerse  it  in  water  containing  some  sodium  amalgam,  and 
slightly  acidulated  with  acetic  acid. 

DETERMINATION   OF   THE   NATURE   OF   THE   HAIR. 

In  examinations  of  this  character  use  is  made  of  the 
microscope.  The  hair  to  be  examined  is  suspended  in  syrup, 
oil,  or  glycerine  and  placed  between  two  thin  glass  plates. 
Human  hair  is  sometimes  cylindrical ;  sometimes  flattened. 
It  consists  either  of  a  central  canal,  or  of  a  longitudinal 
series  of  oblong  cavities  which  contain  oily  coloring  matter, 
and  possesses  the  same  diameter  throughout  its  entire  length. 
The  brown  hair  of  the  beard  and  whiskers,  medium-sized 
chestnut  hair,  the  hair  of  a  young  blonde  girl,  and  the 
downy  hair  of  a  young  man  possess  respectively  a  diameter 
of  0.03  to  0.15  ;  0.08  to  0.09  ;  0.06  ;  and  0.015  t°  0.022 
millimetres.  These  exhibit  on  the  surface  slightly  projecting 
scales,  which  are  irregularly  sinuous  at  the  border,  separated 
from  each  other  by  a  space  of  about  o.oi  m.m.,  and  are 
transparent,  whatever  may  be  their  color. 

The  hair  of  ruminants  is  short  and  stiff,  and  is  character- 
ized by  containing  cavities  filled  with  air.  Wool,  however, 


ioo  LEGAL  CHEMISTRY. 

forms  an  exception,  as  it  consists  of  entire  hairs,  homogeneous 
in  appearance  and  possessing  imbricated  scales,  which  bestow 
upon  it  the  property  of  being  felted. 

The  hair  of  the  horse,  ox  and  cow  never  exceeds  12  m.m. 
in  length,  and  is  tapering,  its  diameter  gradually  diminishing 
from  the  base.  It  is  perfectly  opaque,  and  does  not  appear 
to  possess  a  central  canal ;  has  a  reddish  color,  and  frequently 
exhibits  lateral  swellings,  from  which  small  filaments  occa- 
sionally become  detached,  in  the  same  manner  as  a  twig 
separates  itself  from  the  parent  branch. 

EXAMINATION  OF  FIRE-ARMS. 

(Proposed  by  M.  Boutigny^) 

The  examination  of  fire-arms  is  sometimes  useful  in  deter- 
mining the  date  at  which  a  weapon  has  been  discharged  or 
reloaded.  The  methods  used  in  examinations  of  this  nature 
vary,  as  the  weapon  under  inspection  is  one  provided  with  a 
flint  or  an  ordinary  percussion  lock.  The  value  of  the  tests 
employed  is  also  affected  by  the  kind  of  powder  used ;  /.  e., 
whether  common  gunpowder,  gun-cotton  or  white  gunpowder 
(prepared  by  mixing  yellow  prussiate  of  potassa,  chlorate  of 
potassa  and  sugar)  has  been  taken. 


THE   GUN   IS   PROVIDED  WITH  A  FLINT-LOCK,  AND  WAS   CHARGED 
WITH   ORDINARY   POWDER. 

In  case  the  weapon  has  been  wiped  or  exposed  to  moist- 
ure subsequent  to  its  seizure,  it  is  impossible  to  form  any 
conclusion  as  to  the  date  of  its  discharge,  etc.  It  is  therefore 
advisable,  upon  receiving  the  weapon,  to  carefully  wrap  the 


EXAMINATION  OF  FIRE-ARMS.  101 

lock  in  a  woollen  cloth,  and  to  close  the  barrel.  The  exterior 
of  the  gun  is  at  first  submitted  to  a  careful  examination,  and 
notice  taken  of  the  approximate  thickness  of  any  existing  rust 
spots.  The  fire-pan  and  adjacent  portion  of  the  barrel  are 
also  examined  by  aid  of  a  magnifying  glass,  especial  attention 
being  given  to  the  detection  of  traces  of  a  moist  and  pulveru- 
lent incrustation  of  a  greyish  or  blackish  color,  formed  by  the 
combustion  of  the  gunpowder,  and  of  crystals  of  sulphate  of 
iron.  If  the  weapon  is  loaded,  the  wad  is  withdrawn  and  the 
color  of  its  cylindrical  portion  and  of  the  powder,  as  well  as 
the  size  of  the  ball  or  shot,  noted. 

This  preliminary  examination  ended,  the  barrel  and  fire- 
pan are  separately  washed  with  distilled  water,  and  the  wash- 
ings passed  through  filter  paper  which  has  previously  been 
well  washed,  first  with  pure  hydrochloric  acid,  then  with  dis- 
tilled water.  The  filtrate  is  next  divided  into  three  portions, 
and  these  separately  examined  for:  (i)  sulphuric  acid,  by 
addition  of  chloride  of  barium  ;  (2)  for  iron,  by  oxidizing  the 
salts  contained  in  the  fluid  with  a  few  drops  of  nitric  acid  and 
adding  a  solution  of  ferrocyanide  of  potassium,  the  presence 
of  iron  being  indicated  by  the  formation  of  a  blue  coloration, 
or  a  blue  precipitate  ;  and  (3)  for  sulphides,  by  means  of  a 
solution  of  subacetate  of  lead. 

If  a  bluish-black  incrustation  is  discovered  on  the  fire-pan 
or  on  the  neighboring  portions  of  the  barrel,  and  both  rust  and 
crystals  of  sulphate  of  iron  are  absent,  and  the  washings,  which 
were  originally  of  a  light-yellow  color,  assume  a  chocolate- 
brown  coloration  upon  the  addition  of  solution  of  subace- 
tate of  lead,  the  gun  has  been  discharged  within  two  hours  at 
the  longest. 

If  the  incrustation  possesses  a  lighter  color  and  traces  of 
iron  have  been  detected  in  the  washings,  but  neither  rust  nor 


102  LEGAL  CHEMISTRY. 

crystals  have  been  discovered  on  the  barrel  or  fire-pan,  the  wea- 
pon has  been  discharged  more  than  two,  but  less  than  twenty-four 
hours. 

In  case  minute  crystals  of  sulphate  of  iron  and  spots  of 
rust  are  found,  and  the  washings  contain  iron  in  a  considerable 
quantity,  the  weapon  has  been  discharged  at  least  twenty-four 
hours,  at  the  longest  ten  days. 

If  the  quantity  of  rust  found  is  considerable,  but  iron  is  no 
longer  to  be  detected,  the  discharge  of  the  gun  occurred  ten  days, 
at  the  longest  fifty  days,  previously. 

If  the  weapon  has  been  reloaded  immediately  after  its  discharge 
without  having  been  previously  washed,  the  portions  of  the  wad- 
ding which  have  come  in  contact  with  the  barrel  will  possess  a 
greyish-black  color  during  the  first  four  days,  the  color  grad- 
ually becoming  lighter,  until,  at  the  fifteenth  day,  it  turns  grey 
and  remains  so  permanently.  In  this  case,  the  washings  will 
contain  sulphuric  acid.  The  objection  has  been  advanced  to 
the  '  last  test  that  sulphuric  acid  might  be  discovered,  even 
if  the  gun  had  not  been  discharged,  if  the  paper  of  which 
the  wadding  was  made  contained  plaster.  M.  Boutigny  states, 
however,  that  this  objection  is  untenable,  if  the  wadding 
has  not  been  moistened  by  the  water  introduced  into  the 
barrel. 

In  case  the  gun  has  been  washed  and  dried  before  being  reloaded, 
the  cylindrical  portion  of  the  wadding  possesses  an  ochre- 
yellow  color  up  to  the  first  or  second  day,  assumes  a  decided 
red  hue  on  the  days  following,  and  acquires  a  clear  rusty 
color  on  the  sixth  day.  During  the  fifth  day  the  powder  also 
possesses  a  reddish  appearance,  owing  to  an  admixture  of  rust. 
Sulphuric  acid  is  not  present  in  the  washings. 

If  the  weapon  has  been  reloaded  immediately  after  being  washed, 
the  wadding  possesses  a  greenish-yellow  appearance  for  the  first 


EX  A  MI N A  TION  OF  FIRE- A  RMS.  1 03 

few  hours,  and  subsequently  acquires  a  reddish  color,  as  in  the 
preceding  case. 

If,  finally,  the  barrel  has  been  washed  with  turbid  lime-water, 
rust  is  still  to  be  found  and  the  wadding  possesses  the  color 
mentioned  above.  The  following  colorations  are  also  to  be 
observed  in  case  the  gun  has  not  been  washed,  or  has  been 
dried  near  a  fire  : 

BARREL  DRIED  NEAR  A  FIRE.  UNWASHED  BARREL. 

After  i  day slight  reddish  yellow  color  -  -greenish  yellow  color, 

—  2  or  3  days  -  -  -  a  little  darker  "     -  -  reddish-brown       " 

—  4  days a  redder  "     -  -reddish-brown       " 

—  5  or  more  days  -  a  rusty-red  "     -  -  rusty-red. 

THE   GUN    IS    NOT   PROVIDED   WITH   A   FLINT   LOCK. 

At  present  weapons  having  flint-locks  have  almost  entirely  gone 
out  of  use  and  have  been  superseded  by  the  ordinary  percussion 
gun ;  these  latter,  in  turn,  are  being  gradually  replaced  by 
breech-loaders,  charged  with  or  without  a  metallic  cartridge.  The 
indications  obtained  in  the  preceding  examinations  by  means  of 
the  fire-pan,  will  therefore  disappear  ;  the  results  given  by  the 
inspection  of  the  barrel  may  possibly  hold  good.  In  regard 
to  breech-loaders,  all  the  useful  indications  furnished  by  the 
coloration  of  the  wadding  and  powder  fail  to  occur ;  the  latter 
being  enclosed  either  in  a  paper  cylinder  or  in  a  copper  socket. 
The  fact  that  gun  cotton  and  white  gunpowder  are  occa- 
sionally made  use  of,  adds  to  the  difficulty  of  obtaining  reliable 
results  by  the  mere  inspection  of  a  weapon.  White  gunpowder 
does  not  oxidize  the  gun,  fails  to  give  rise  to  any  salt  of  iron, 
and  possesses  a  white  color ;  gun-cotton  produces  distinctive 
indications  varying  with  its  purity.  Owing  to  these  facts,  it  is 
evident  that  the  method  proposed  by  M.  Boutigny  is  of  no  real 


104 


LEGAL  CHEMISTRY. 


value,  save  in  the  rare  instances  where  a  gun  provided  with  a 
fire-pan,  and  charged  with  ordinary  powder,  is  under  examina- 
tion, and  the  question  of  the  lapse  of  time  since  the  discharge 
of  a  weapon  must  remain  undetermined  so  far  as  scientific 
tests  are  concerned. 

DETECTION  OF  HUMAN  KK.TIAINM  IN  THE  A  Nil  KM  OF  A 
FIRE-PLACE. 

This  class  of  examinations  is  particularly  necessary  when 
the  crime  of  infanticide  is  suspected.  As  the  complete  incine- 
ration of  a  cadaver  is  a  long  and  difficult  operation,  it  frequent- 
ly occurs  that  bones — partially  or  completely  carbonized, 
but  retaining  their  original  form — are  discovered  by  the  careful 
examination  of  the  ashes  of  the  fire-place  in  which  the  com- 
bustion was  accomplished. 

When  this  is  not  the  case  and  complete  incineration  and 
disaggregation  have  occurred,  recourse  must  be  had  to  the  indi- 
cations furnished  by  a  chemical  analysis.  These  indications 
are  reliable,  however,  only  when  the  certainty  exists  that  bones 
of  animals  have  not  been  consumed  in  the  same  fire-place  ; 
otherwise,  the  results  obtained  are  entirely  worthless,  the  reac- 
tions given  by  ashes  of  animal  bones  being  identical  with  those 
produced  by  the  ashes  of  a  human  body.  Two  tests  are  em- 
ployed to  detect  the  presence  of  bones  in  the  residue  left  by 
the  combustion  of  animal  matter. 

i.  A  portion  of  the  ashes  is  placed  in  a  silver  crucible, 
heated  with  potassa,  and  the  mass  afterwards  treated  with  cold 
water.  If  animal  matter  is  contained  in  the  consumed  mate- 
rials, cyanide  of  potassium  will  be  present  in  the  aqueous 
solution.  In  order  to  detect  this  salt,  the  fluid  is  acidu- 
lated with  hydrochloric  acid,  and  a  solution  of  persulphate 
of  iron  added :  the  formation  of  a  blue  precipitate  indicates 
the  presence  of  the  cyanide. 


EXAMINATION  OF  WRITINGS.  105 

2.  The  ashes  are  next  examined  for  phosphate  of  lime.  As 
wood,  coal,  and  the  other  substances  usually  employed  for 
heating  purposes  contain  none  or  little  of  this  salt,  its  detec- 
tion in  a  notable  quantity  would  lead  to  the  inference  that  bones 
have  been  consumed.  The  ashes  are  allowed  to  digest  for 
twenty-four  hours  with  one-quarter  of  their  weight  of  sulphuric 
acid.  Water  is  next  added  to  the  pasty  mixture,  and  the  fluid 
filtered.  If  phosphate  of  lime  be  present,  it  is  converted  by 
this  treatment  into  a  soluble  acid  phosphate,  which  passes  into 
the  filtrate.  Upon  adding  ammonia  to  the  filtrate,  a  precipi- 
tate of  neutral  phosphate  of  lime  is  formed,  neutral  phosphate 
of  ammonia  remaining  in  solution.  The  fluid  is  again  filtered, 
the  filtrate  acidulated  with  nitric  acid,  and  then  boiled  with  a 
solution  of  molybdate  of  ammonia  likewise  acidulated  with  nitric 
acid :  in  presence  of  a  phosphate,  a  yellow  precipitate,  or  at  least 
a  yellow  coloration  of  the  fluid,  will  be  produced.  It  has  been 
stated  that  the  disengagement  of  sulphuretted  hydrogen,  upon 
treating  the  ashes  with  sulphuric  acid,  is  an  indication  that 
the  combustion  of  a  human  body  has  occurred ;  this  reac- 
tion is,  however,  valueless,  inasmuch  as  coal  and  certain  vege- 
table ashes  likewise  evolve  the  gas  when  subjected  to  the  same 
treatment. 

EXAMINATION  OF  WHITINGS. 

Contracts,  checks,  etc.,  are  frequently  altered  with  criminal 
intent,  either  by  erasing  the  portion  of  the  writing  over  the 
signature  and  substituting  other  matter,  or  by  changing  cer- 
tain words,  in  order  to  modify  the  signification  of  a  sen- 
tence. 

Writings  are  altered  either  by  erasure  or  by  washing. 
Erasure,  although  more  easily  executed,  is  seldom  employed, 

5* 


I06  LEGAL  CHEMISTRY. 

as  it  renders  the  paper  thin  in  places,  and  in  this  way  leaves 
effects  apparent  even  to  the  naked  eye,  and,  although  the 
original  thickness  can  be  restored  by  application  of  sandarac 
or  alum,  these  substances  possess  properties  differing  from 
those  exhibited  by  paper,  and  may,  moreover,  be  completely 
removed,  thus  exposing  the  thinning  of  the  paper. 

In  case  washing  by  means  of  chlorine  has  been  resorted 
to,  the  sizing — which  renders  the  paper  non-bibulous,  and  which 
is  only  with  difficulty  replaced — may  have  been  removed. 
Formerly  paper  was  sized  by  immersion  in  a  solution  of  gela- 
tine ;  at  present,  however,  a  soap  of  resin,  or  wax,  and 
alumina  (a  little  starch  being  added)  is  more  commonly  used. 
In  the  latter  case,  the  sizing  is  less  easily  removed  by  the 
action  of  water  than  when  the  gelatine  preparation  is  employ- 
ed ;  the  detection  of  its  attempted  restoration  is  also  a  matter 
of  less  difficulty,  as  gelatine  would  be  employed  for  this  pur- 
pose, and  this  body  possesses  properties  different  from  those 
exhibited  by  the  substances  normally  contained  in  paper  : 
iodine,  for  instance,  which  imparts  a  yellow  color  to  gelatine, 
turns  starch  violet-blue.  In  order  to  detect  the  alteration  of 
a  writing,  the  following  examinations  are  made : 

i°.  The  paper  is  carefully  examined  in  all  of  its  parts,  and 
in  various  positions,  by  aid  of  a  lens.  In  this  way,  either 
thinned  points,  caused  by  erasure,  or  remaining  traces  of 
words,  may  possibly  be  discovered. 

2°.  The  paper  is  next  placed  upon  a  perfectly  clean  piece 
of  glass,  and  completely  and  uniformly  moistened  with  \vater. 
The  glass  is  then  removed,  and  the  transparency  of  the  paper 
examined  by  aid  of  a  lens.  When  uniform  transparency  is 
exhibited,  and  certain  portions  are  neither  more  transparent 
nor  more  opaque  than  the  rest  of  the  paper,  it  is  probable  that 
erasure  has  not  been  attempted.  If,  on  the  other  hand, 


EXAMINA  TION  OF  WRITINGS. 


107 


opaque  points  are  observed,  it  is  almost  certain  that  letters 
have  been  erased,  and  sandarac,  which  is  not  affected  by 
water,  subsequently  applied.  In  case  transparent  points  are 
detected,  there  is  reason  to  suspect  that  words  have  been 
removed,  and  the  spots  either  left  intact  or  afterwards  coated 
with  a  substance  soluble  in  water,  such  as  alum. 

3°.  The  paper  is  dried  and  the  above  operation  repeated 
with  alcohol  of  87  percent  Indications  may  now  be  observed 
which  failed  to  occur  in  the  treatment  with  water ;  as  well  as 
these  latter  confirmed.  As  alcohol  dissolves  sandarac,  the 
points  that  formerly  appeared  opaque  may  now  become  trans- 
parent. 

4°.  The  paper  is  again  dried,  then  placed  under  a  sheet  of 
very  thin  silk-paper,  and  a  warm  iron  passed  over  it.  This 
operation  frequently  causes  the  reappearance  of  words  that 
have  been  partially  obliterated.  It  is  also  advisable — as  sug- 
gested by  M.  Lassaigne — to  expose  the  paper  to  the  action  of 
iodine  vapors.  If  alteration  has  not  been  attempted,  the  paper 
will  acquire  an  uniform  color  ;  yellow,  if  sized  with  gelatine  ; 
violet  blue,  if  sized  with  the  mixture  of  soap,  resin  and  starch. 
When,  on  the  contrary,  a  subsequent  sizing  of  gelatine  has  been 
applied  in  order  to  mask  the  alteration — the  paper  having  been 
originally  sized  with  the  above  mixture — it  will  assume  in  some 
portions  a  yellow,  in  others  a  violet-blue  color. 

5°.  It  is  ascertained  whether  the  paper  possesses  an  acid  reac- 
tion. If  so,  its  acidity  may  result  from  the  presence  of  hydro- 
chloric acid,  in  case  the  paper  was  washed  with  chlorine,  or  of 
other  acids.  Alum,  used  to  disguise  erasure,  would  also  cause 
an  acid  reaction.  The  mere  detection  of  acidity  is,  in  itself,  of 
little  importance,  as,  in  the  manufacture  of  paper,  the  pulp  is 
bleached  by  means  of  chlorine,  and  this  reagent  may  not  have 
been  entirely  removed  by  washing.  If,  however,  the  paper  is 


io8  LEGAL  CHEMISTRY. 

acid  only  in  certain  spots,  and  these  points  produce  a  red 
coloration  upon  blue  litmus  paper,  having  the  form  of  letters, 
the  indication  is  of  value.  In  order  to  ascertain  if  this  be  the 
case,  it  is  advisable,  before  wetting  the  paper,  to  slightly  press 
it  upon  a  sheet  of  moist  litmus  paper  :  the  acid  spots  will  then 
leave  a  reddish  trace  upon  the  latter. 

6°.  The  manuscript  under  examination  is  again  spread 
upon  a  glass-plate,  and  a  solution  of  tannin  (or  preferably,  a 
solution  of  ferrocyanide  of  potassium  containing  one  per 
cent,  of  the  salt,  and  acidulated  with  acetic  acid)  applied  by 
means  of  a  brush.  If  the  original  writing  was  executed  with 
ordinary  ink  (which  has  as  its  base  tannate  of  iron),  and  the 
washing  has  been  but  imperfectly  performed,  it  is  quite  possible 
that  a  blue  coloration  will  be  produced  by  the  action  of  the 
ferrocyanide.  It  is,  however,  often  necessary  to  apply  the 
above  reagents  several  times  before  the  original  writing 
becomes  apparent ;  indeed,  in  some  cases  months  have  elapsed 
before  the  reaction  has  occurred. 

In  case  the  alteration  or  destruction  of  the  document  is 
feared  in  the  above  test,  it  is  well  to  previously  provide  the 
court  with  a  certified  copy,  and  then  proceed  with  the  examina- 
tion. 

7°.  If  the  paper  possesses  a  friable  appearance,  it  has  pos- 
sibly been  washed  with  sulphuric  acid.  This  property  may 
however  originate  from  other  causes,  and  the  presence  of  the 
acid  should  be  confirmed  by  washing  the  document  with  dis- 
tilled water,  and  adding  a  solution  of  chloride  of  barium  to 
the  washings.  The  precipitate  should  form  in  a  considerable 
quantity,  as  a  slight  cloudiness  could  be  due  to  sulphates 
contained  in  the  water  used  in  the  preparation  of  the  pulp. 

If  much  sulphuric  acid  be  present,  it  may  be  so  concen- 
trated by  heating  as  to  cause  the  carbonization  of  the  paper. 


EXAMINA  TION  OF  WRITINGS. 


109 


8°.  It  is  also  well,  should  washing  with  sulphuric  acid  be 
suspected,  to  ascertain,  by  aid  of  a  lens,  if  the  filaments  on 
the  surface  of  the  manuscript  possess  an  inflated  appear- 
ance. This  would  be  caused  by  the  escape  of  carbonic  acid, 
originating  from  the  action  of  sulphuric  acid  upon  the  car- 
bonates contained  in  the  water  used  in  the  manufacture  of 
the  paper. 

9°.  Old  ink  is  more  difficult  to  remove  than  new,  and  it  is 
therefore  sometimes  possible  to  cause  the  reappearance  of 
old  writings,  over  which  words  have  been  subsequently  writ- 
ten. For  this  purpose,  a  solution  containing  50  per  cent,  of 
oxalic  acid  is  applied  with  a  fine  brush  over  the  suspected 
points.  As  soon  as  the  ink  disappears,  the  acid  is  immedi- 
ately removed  by  washing  with  water,  and  the  paper  dried. 
Upon  now  repeating  the  operation,  the  presence  of  a  former 
writing  may  be  detected  after  the  complete  disappearance  of 
the  words  last  written. 

10°.  According  to  M.  Lassaigne,  when  the  same  ink  has 
not  been  used  throughout  a  document,  washing  with  dilute 
hydrochloric  acid  will  demonstrate  the  fact.  This  acid,  while 
causing  the  gradual  obliteration  of  characters  written  with 
ordinary  ink — the  shade  of  the  paper  not  being  altered — 
produces  a  red  color,  if  ink  containing  log-wood  has  been 
employed,  and  a  green  coloration,  in  case  the  ink  used 
contained  Prussian  blue. 

The  expert  may  possibly  be  called  upon  to  give  evidence 
as  to  the  existence  of  a  "  trompc-F oeil ;  "  as  was  the  case  in 
the  trial  of  M.  de  Preigne,  which  took  place  at  Montpelier  in 
1852.  A  "  trompe-Fotil "  consists  of  two  sheets  of  paper, 
glued  together  at  the  edges,  but  having  the  upper  sheet  shorter 
than  the  other  which  therefore  extends  below  it.  This  species 
of  fraud  is  executed  by  writing  unimportant  matter  on  the 


IIO  LEGAL  CHEMISTRY. 

uppermost  sheet,  and  then  obtaining  the  desired  signature, 
care  being  taken  that  it  is  written  on  the  portion  of  the  paper 
projecting  below.  The  signature  having  been  procured,  it  is 
only  necessary  to  detach  the  two  sheets  in  order  to  obtain  a 
blank  paper  containing  the  signature,  over  which  whatever  is 
desired  can  be  inserted.  The  trial  referred  to  above,  was  in 
reference  to  a  receipt  for  3,000  francs.  The  expert, 
upon  placing  pieces  of  moistened  paper  upon  the  sus- 
pected document,  noticed  that  they  adhered  to  certain 
points,  and  that  these  formed  a  border  around  the  paper  but 
passing  above  the  signature.  The  fraudulency  of  the  act  was 
thus  established,  and  so  recognized  by  the  court,  although  the 
accused  was  acquitted  by  the  jury. 

Numerous  means  have  been  proposed,  in  order  to  render 
the  falsification  of  documents  a  matter  of  difficulty.  The 
most  reliable  of  these  is  the  use  of  "  Grimpe's  safety-paper," 
containing  microscopic  figures,  the  reproduction  of  which  is 
impossible.  Unfortunately,  up  to  the  present,  the  government 
has  adopted  methods  less  sure. 

•* 

EXAMINATION  OF  WRITINGS  IN  CASES  WHERE  A  SYM- 
PATHETIC INK  HAS  BEEN  USED. 

Sympathetic  inks  are  those  which,  although  invisible  at  the 
time  of  writing,  become  apparent  by  the  application  of  certain 
agents.  They  are  of  two  classes  :  those  which  are  rendered 
visible  by  the  mere  application  of  heat,  such  as  chloride  of 
cobalt,  or  the  juice  of  onions ;  and  those  which  are  brought 
out  only  by  the  action  of  a  reagent.  The  inks  of  the  second 
class  most  frequently  used  are  solutions  of  acetates  of  lead, 
and  other  metals  which  give  a  colored  sulphide  when  treated 
with  sulphuretted  hydrogen.  Characters  written  with  a  solu- 
tion of  ferrocyanide  of  potassium  acquire  a  blue  color,  if 


EXAMINATION  OF  WRITINGS.  m 

washed  with  a  solution  of  perchloride  of  iron.  It  is  scarcely 
necessary  to  add  that  the  latter  solution  can  be  used  as  the 
ink,  and  the  ferrocyanide  as  the  developer. 

When  the  presence  of  characters  written  with  a  sympa- 
thetic ink  is  suspected,  the  document  is  examined  as  follows : 

1.  The  paper  is  at  first  warmed  :  if  the  ink  used  is  of  the 
first  class,  the  characters  will  now  become  legible ;  otherwise 
the  examination  is  continued  as  below. 

2.  The  paper  is  exposed  to  the  action  of  steam,  in  order  to 
moisten  the  ink  present  (care  being  taken  to  avoid  dissolving 
the  characters),  and  a  current  of  sulphuretted  hydrogen  allow- 
ed to  act  upon  it.     If  the  ink  used  consists  of  a  lead,  bismuth, 
or  gold  salt,  a  black  coloration  will  ensue  ;  if  salts  of  cadmium 
or  arsenic  were  employed,  the  characters  will  acquire  a  yellow 
color ;  if,  finally,  a  salt  of  antimony  was  used,  a  red  coloration 
will  be  produced. 

3.  If -no  coloration  was  caused  by  the  action  of  sulphuret- 
ted hydrogen,  it  is  probably  that  either  a  solution  of  ferrocy- 
anide of  potassium  or  a  persalt  of  iron  has  been  resorted  to. 
Each  of  these  solutions  is  separately  applied  on  a  small  por- 
tion of  paper  by  means  of  a  brush,  and  notice  taken  if  the 
characters  become  visible.     The  solution  that  produced  the 
change  is  then  applied  over  the  entire  sheet. 

4.  In  case  only  negative  results  were  obtained  in  the  preced- 
ing operations,  it  must  not  yet  be  concluded  that  a  sympa- 
thetic ink  has   not  been  used,  although  we  are  left  without 
further  recourse  to  chemical  tests.     Numerous  organic  com- 
pounds may  have  been  resorted  to,  the  detection  of  which  is 
almost  impossible ;  moreover,  if  a  mistake  was  made  in  regard 
to  the  preparation  supposed  to  have  been  used,  the  reagents 
employed  for  its  detection  may  render  the  discovery  of  an- 
other ink  absolutely  impossible.     It  is  therefore  often  neces- 


H2  LEGAL  CHEMISTRY. 

sary  to  apply  mechanical  tests.  For  this  purpose,  the  paper 
is  spread  upon  a  glass  plate,  uniformly  moistened  with  water, 
and  a  second  plate  placed  over  it :  if  the  characters  were  writ- 
ten with  a  pulverulent  substance  suspended  in  water  or  muci- 
lage, they  may  often  be  observed  upon  examining  the  transpar- 
ency of  the  paper.  In  case  the  substance  used  is  both  colorless 
and  soluble,  the  detection  of  the  written  characters  will  be 
more  difficult ;  still,  indelible  traces  may  possibly  have  been 
left  by  the  pen.  If,  however,  the  ink  employed  is  a  colorless 
and  transparent  organic  compound  of  rare  occurrence,  and  was 
applied  with  a  fine  pencil-brush  which  failed  to  affect  the 
paper,  it  must  be  acknowledged  that  little  or  nothing  can  be 
definitely  determined  as  to  its  presence  or  absence. 

FALSIFICATION  OF  COINS  AN»  ALLOYS. 

In  all  civilized  countries  a  fixed  standard  for  coins  and 
precious  alloys  is  established  by  law,  in  order  to  prevent  the 
perpetration  of  frauds  which  would  be  of  serious  injury  to  the 
public  welfare.  The  substitution  of  coins  consisting  of  an 
alloy  inferior  in  value  to  the  standard  fixed  by  law,  is  too 
advantageous  a  fraud  not  to  be  often  attempted. 

Coins  are  most  frequently  altered  by  clipping ;  by  stuffing, 
that  is,  by  boring  the  coin  and  inserting  an  alloy  of  small  value  ; 
by  doubling,  which  operation  consists  in  covering  its  face  with 
two  thin  laminae  taken  from  a  genuine  coin  ;  and  by  applying 
a  coating  of  gold  or  silver  by  means  of  electro-plating. 

In  order  to  ascertain  if  a  coin  has  been  counterfeited,  its 
weight  should  at  first  be  determined.  If  it  has  been  clipped, 
or  consists  of  an  alloy  possessing  a  density  less  than  that  of 
silver  or  gold,  the  fact  is  immediately  demonstrated  by  its 
decreased  gravity. 


EXAMINATION  OF  COINS,  ETC.  113 

The  coin  is  further  tested  by  throwing  it  down  upon  a  hard 
substance  :  gold  and  silver  give  a  ringing  sound,  whereas  the 
majority  of  other  metals  produce  a  dull  sound. 

The  result  obtained  by  this  latter  test  often  fails  to  be 
reliable.  A  skilful  counterfeiter  may  prepare  an  alloy  equally 
sonorous  and  heavy  as  silver  or  gold ;  in  fact,  M.  Duloz  ex- 
hibited to  the  author  an  alloy,  prepared  by  him,  possess- 
ing the  density,  sonorousness  and  lustre  of  silver ;  the  com- 
position of  which,  for  obvious  reasons,  has  not  been  published. 

In  instances  of  this  nature  the  fusibility  of  the  coin  should 
be  determined,  and  the  result  obtained  compared  with  the 
melting  point  of  the  legal  alloy,  or,  this  failing,  a  chemical 
analysis  executed.  In  order  to  perform  the  latter  test,  the 
coin  under  examination  is  boiled  with  nitric  acid  :  all  metals 
are  dissolved,  with  exception  of  gold  and  platinum,  which 
remain  unaltered,  and  tin  and  antimony,  which  are  converted 
respectively  into  metastannic  and  antimonic  acids.  The  fluid 
is  filtered,  the  insoluble  residue  well  washed,  and  then  boiled 
with  hydrochloric  acid,  which  dissolves  the  metastannic  and 
antimonic  acids.  The  solution  is  again  filtered,  and  the  second 
residue  dissolved  in  aqua  rcgia.  The  metals  dissolved  in  the 
several  filtrates  are  then  detected,  either  by  the  processes 
previously  given  for  the  detection  of  metallic  poisons,  or  by 
the  more  complete  methods  contained  in  works  on  chemical 
analysis.  This  qualitative  test  is,  however,  insufficient,  in  case 
the  falsification  consisted  in  merely  diminishing  the  proportions 
of  the  valuable  metals  contained  in  the  alloy,  without  changing 
its  qualitative  composition  :  it  is  then  necessary  to  execute  a 
quantitative  estimation  of  the  metals  present.  As  this  opera- 
tion requires  considerable  practice  and  the  methods  employed 
are  to  be  found  in  all  treatises  on  quantitative  analysis,  we  will 
not  reproduce  them  here. 


H4  LEGAL  CHEMISTRY. 

EXAMINATION  OF    ALIMENTARY     AND     I'HAU.UAC  E  lr- 
TICAL   SUBSTANCES. 

We  will  next  enumerate  the  methods  employed  in  the 
detection  of  the  principal  adulterations  to  which  flour,  bread, 
oils  of  seeds,  milk,  wines,  vinegar  and  the  sulphate  of  quinine 
are  subjected.  These  researches,  united  with  those  preced- 
ing, fail  to  embrace  all  the  diverse  examinations  which  the 
chemical  expert  may  be  expected  to  execute ;  but  we  do  not 
claim  to  foresee  all  the  contingencies  that  may  arise,  and 
will  describe  the  steps  to  be  pursued  in  instances  which  are 
anticipated,  at  the  same  time  indicating  general  methods 
applicable  to  cases  not  here  included. 

FLOUR  AND  BREAD. 

The  adulterations  to  which  flour  and  bread  are  exposed 
usually  consist  in  adding  damaged  or  an  inferior  grade  of 
flour  to  wheaten  flour,  or  in  disguising  the  presence  of  a 
poor  quality  of  flour  by  the  addition  of  mineral  substances, 
such  as :  plaster,  chalk,  lime,  alum,  and  sulphate  of  copper. 

Good  flour  has  a  white  color,  possessing  a  slightly  yellow 
tinge,  but  is  entirely  free  from  red,  grey  or  black  specks.  It 
is  soft  to  the  touch  and  adheres  to  the  fingers,  acquiring,  when 
compressed  in  the  hand,  a  soft  cushion-like  form.  If  mixed 
with  water,  it  forms  an  elastic,  homogeneous,  but  slightly  co- 
herent dough,  which  can  be  extended  out  in  thin  layers. 

Flour  of  an  inferior  quality  possess  a  dull  white  color,  and 
does  not  assume  the  cushion-like  condition  mentioned  above, 
when  pressed  in  the  hand,  but  escapes  between  the  fingers  : 
the  dough  formed  is  of  a  poorer  quality. 

Flour  which  has  been  damaged  by  moisture  has  a  dull  or 


FLOUR  AND  BREAD.  H5 

reddish-white  hue,  and  possesses  a  mouldy,  or  even  a  noxious, 
odor,  as  well  as  a  bitter  and  nauseous  taste  which  produces 
a  marked  acid  sensation  in  the  throat.  Occasionally  the 
presence  of  moisture  causes  the  growth  of  fungi,  the  introduc- 
tion of  which  in  the  digestive  organs  would  cause  serious 
results. 

The  constituents  of  pure  flour  are : 

Gluten. 

Starch,  in  the  proportion  of  50  to  75  per  cent. 

Dextrine,  in  the  proportion  of  several  per  cent. 

Glucose,  in  the  proportion  of  several  per  cent. 

Salts,  remaining  in  the  ash  obtained  by  the  calcination  of 
the  flour,  in  a  proportion  not  exceeding  2  per  cent. 

Water,  of  which  it  loses  12  to  15  per  cent.,  at  the  heat 
of  a  water-bath,  and  15  to  20  per  cent.,  at  a  temperature  of 
1 60°. 

Bran,  (ligneous  and  fatty  matter,)  in  a  very  small  propor- 
tion, when  the  flour  has  been  properly  bolted. 

In  the  process  of  bread-making,  the  gluten  undergoes 
fermentation  by  the  action  of  the  leaven  and  liberates  carbonic 
acid,  which  causes  the  dough  to  become  porous  and  swell  up, 
or,  as  it  is  termed,  to  rise.  Bread  contains  the  same  substances 
as  flour,  but  gluten  and  starch  are  present  in  a  state  that 
does  not  admit  of  their  separation  by  mechanical  means,  and 
glucose,  if  present  at  all,  exists  in  a  smaller  quantity  :  the 
proportion  of  dextrine  and  water  is,  on  the  other  hand,  con- 
siderably increased.  The  bread  of  the  Paris  city  bakeries 
contains  40  per  cent,  of  water — the  crumb,  which  forms  £  of 
the  weight  of  the  bread,  containing  45  per  cent. ;  the  crust, 
which  constitutes  the  remaining  £,  containing  15  per  cent. 
In  army  bread  43  per  cent,  of  water  are  contained — the 
crumb,  which  constitutes  f  of  the  weight  of  the  bread,  holding 


n6  LEGAL  CHEMISTRY. 

50  per  cent. ;  the  crust  which  forms  the  remaining  £,  con- 
taining 15  per  cent. 

The  addition  of  common  salt  naturally  increases  the  pro- 
portion of  ash  left  upon  calcining  bread. 

Water  is  contained  in  stale  bread  in  the  same  quantity  as 
in  fresh  bread  ;  but  exists  in  a  modified  molecular  condition : 
upon  heating  stale  bread,  it  acquires  the  properties  of  fresh 
bread. 

The  following  substances  are  used  in  the  adulteration  of 
wheaten  flour:* 

Potato-starch. 

Meals  of  various  grains  (rice,  barley,  corn,  oats  and  rye). 

Vegetable  meals,  (beans,  horse-beans,  kidney-beans,  peas, 
vetch,  lentils,  etc). 

Darnel  meal. 

Buck- wheat  flour. 

Linseed-meal. 

Mineral  substances  (plaster,  chalk,  lime,  alum,  and  sulphate 
of  copper). 

In  order  to  detect  these  substances,  the  gluten,  the  starch, 
and  the  ash  are  separately  examined. 

a.    EXAMINATION    OF  THE    GLUTEN. 

In  order  to  separate  the  gluten,  two  parts  of  the  flour  to 
be  examined  and  one  part  of  water  are  mixed  into  a  paste, 


*  Most  of  the  substances  here  enumerated  are  rarely,  if  ever,  used  for 
the  adulteration  of  flour  in  this  country.  The  analyst  should,  however, 
give  attention  to  the  examination  for  such  salts  as  alum,  sulphate  of  cop- 
per, plaster,  kaolin,  etc. — Trans. 


FLOUR  AND  BREAD.  117 

and  this  is  placed  in  a  fine  linen  sack,  in  which  it  is  kneaded  under 
a  stream  of  water  so  long  as  the  washings  have  a  turbid  appear- 
ance :  these  are  preserved.  The  gluten  obtained  from  good 
wheaten  flour  possesses  a  light-yellow  color ;  emits  a  stale 
odor ;  and  spreads  out,  when  placed  in  a  saucer.  In  case  the 
flour  has  been  too  strongly  heated  in  the  grinding,  or  other- 
wise badly  prepared,  the  gluten  is  granulous,  difficult  to  collect 
in  the  hand,  and  somewhat  resembles  flint-stone  in  appear- 
ance. 

Gluten  prepared  from  a  mixture  of  equal  parts  of  wheat 
and  rye  is  adhesive,  blackish,  without  homogeneousness, 
spreads  out  more  readily  than  pure  wheaten  gluten,  separates 
easily  and  adheres  somewhat  to  the  fingers. 

Gluten  obtained  from  a  mixture  of  wheat  and  barley  is 
non-adhesive,  of  a  dirty  reddish-brown  color,  and  appears  to 
be  formed  of  intertwined  vermicular  filaments. 

Gluten  formed  from  a  mixture  of  equal  parts  of  wheat  and 
oats  has  a  blackish-yellow  color  and  exhibits,  at  the  surface, 
numerous  small  white  specks. 

The  gluten  from  a  mixture  of  wheat  and  corn  has  a  yellow- 
ish color,  is  non-adhesive,  but  firm,  and  does  not  readily 
spread. 

Gluten  prepared  from  a  mixture  of  wheat  and  leguminous 
flour  is  neither  cohesive  nor  elastic,  and,  if  the  proportion  of 
the  latter  present  be  considerable,  can  be  separated  and 
passed  through  a  sieve,  like  starch. 

The  gluten  obtained  from  a  mixture  of  equal  parts  of 
wheat  and  buck-wheat  flour  is  very  homogeneous,  and  is  as 
easily  prepared  as  the  gluten  from  pure  wheaten  flour.  It 
possesses  when  moist  a  dark-grey  color ;  which  changes  to  a 
deep  black  upon  drying.  The  proportion  of  gluten  in  flour  is 
exceedingly  variable :  good  flour  contains  from  10  to  n  per 


n8  LEGAL  CHEMISTRY. 

cent,  of  dry  gluten ;  poor  flour  from  8  to  9  per  cent,  of  moist 
gluten,  equal  to  about  one-third  of  its  weight  of  the  dry  com- 
pound. 

b.    EXAMINATION   OF   THE   STARCH. 

The  washings  of  the  flour  are  allowed  to  stand  for  some 
time  in  a  conical-shaped  vessel.  As  soon  as  the  amylaceous 
matter  has  entirely  settled  to  the  bottom  of  the  vessel,  the 
greater  portion  of  the  water  is  decanted,  and  the  residual  mass 
brought  upon  a  small  filter  and  allowed  to  dry.  The  residue 
is  then  examined  for  potato  and  rice  starch. 

Potato  starch.  The  grains  of  potato  starch  are  much 
larger  than  those  of  wheaten  starch.  If  a  portion  of  the 
residue  mentioned  above  is  crushed  in  an  agate  mortar,  the 
granules  of  potato  starch  present  are  ruptured,  and  their 
contents  liberated ;  the  wheaten  starch  remaining  unaltered. 
The  mass  is  then  taken  up  with  water,  and  the  fluid  filtered. 
If  potato  starch  be  present,  the  filtrate  will  acquire  a  blue 
color  upon  addition  of  an  aqueous  solution  of  iodine  ;  other- 
wise, a  yellow  or  violet-rose  coloration  is  produced.  It  is 
necessary  to  avoid  crushing  the  residue  for  too  long  a  time,  as 
the  granules  of  wheaten  starch  would  also  become  ruptured  by 
prolonged  comminution. 

Besides  the  difference  presented  by  potato  starch  in  the 
size  of  the  granules  in  comparison  to  those  of  wheaten  starch, 
the  former  swell  to  ten  or  fifteen  times  the  volume  of  the 
latter,  when  treated  with  a  solution  of  potassa :  wheaten 
starch  granules  are  not  affected  by  the  treatment,  if  the  so- 
lution used  does  not  contain  more  than  2  percent,  of  the  salt. 
The  results  obtained  by  the  above  operation  should  be  con- 
firmed by  a  microscopic  examination. 


FLOUR  AND  BREAD. 


A  portion  of  the  residue  is  moistened  with  solution  of 
iodine,  then  carefully  dried,  and  placed  on  the  slide  of  a 
microscope.  The  mass  is  next  moistened  with  a  solution 
containing  2  per  cent,  of  potassa,  and  examined.  The  addi- 
tion of  iodine  causes  the  potato  starch  granules  to  acquire  a 
blue  color,  and  renders  their  shape  and  volume  more  easily 
perceptible  ;  thus  allowing  the  two  varieties  of  starch  to  be 
readily  distinguished.  Fig.  13,  represents  the  relative  size  of 
the  granules  as  observed  under  the  microscope.* 

The  presence  of  potato  starch  in  bread  is  also  detected  by 
crushing  a  small  portion  of  the  sample  under  examination  on 
the  glass,  and  then  adding  a  few  drops  of  the  alkaline  solu- 
tion. 

Rice  and  Corn. — If  rice  or  corn  meal  have  been  mixed  with 
the  flour,  angular  and  translucent  fragments  (Fig.  14)  are  ob- 
served in  the  microscopic  examination.  Corn  meal  acquires  a 
yellow  color,  if  treated  with  dilute  potassa  solution. 


I 


*  It  may  be  added,  as  a  distinguishing  property,  that  granules  of  potato 
starch,  when  viewed  in  polarized  light  by  aid  of  a  Nicol's  prism,  present 
a  well-defined  black  cross,  corresponding  to  the  hilum ;  wheaten-stareh 
fails  to  exhibit  this  phenomenon. — Trans. 


120  LEGAL  CHEMISTRY. 

MISCELLANEOUS  TESTS. 

Linseed  and  rye  meals. — If  linseed  meal  is  moistened  with 
an  aqueous  solution  containing  14  per  cent  of  potassa  and  ex- 
amined under  the  microscope,  numerous  minute  characteristic 
granules,  smaller  than  the  grains  of  potato-starch,  are  observed. 
These  possess  a  vitreous  appearance,  sometimes  a  reddish 
coior,  and  usually  form  in  squares  or  very  regular  rectangles. 
The  test  is  equally  applicable  to  bread.  The  detection  of  lin- 
seed and  rye  meals  is  simultaneously  effected  by  exhausting  the 
suspected  flour  with  ether,  then  filtering  the  solution  and  allow- 
ing it  to  evaporate.  If  the  flour  contains  rye,  the  oil  left  by 
the  evaporation,  when  heated  with  a  solution  of  mercury 
in  concentrated  nitric  acid,  is  converted  into  a  solid  sub- 
stance having  a  fine  red  color ;  but  it  remains  unaltered, 
if  entirely  due  to  linseed.  In  case  the  oil  becomes  solid- 
ified, the  mercury  salt  present  should  be  removed  by  wash- 
ing with  water,  the  residue  taken  up  with  boiling  alcohol  of 
36°  B.  and  the  solution  filtered  :  upon  evaporating  the  alco- 
holic filtrate,  a  residue  is  obtained  consisting  of  the  linseed 
oil  present. 

Buckwheat. — Flour  adulterated  with  buckwheat  is  less  soft 
to  the  touch,  does  not  pack  as  easily,  and  passes  more  readily 
through  a  sieve  than  pure  wheaten  flour.  It  presents,  here 
and  there,  blackish  particles,  due  to  the  perisperm  of 'the  grain, 
and  has  a  dirty-white  color.  As  previously  remarked,  the  glu- 
ten obtained  from  a  mixture  of  buckwheat  and  wheaten  flour 
possesses  a  grey  or  even  a  black  color.  The  starch  furnished 
by  buckwheat  flour  exhibits  polyhedral  agglomerations,  analo- 
gous to  those  presented  by  corn. 

Darnel. — The  use  of  darnel  in  the  adulteration  of  wheaten 
flour  may  give  rise  to  serious  sanitary  results.  To  effect  its 


FLOUR  AND  BREAD.  121 

detection,  the  flour  to  be  examined  is  digested  with  alcohol  of 
35° B.  :  if  the  flour  be  pure,  the  alcohol  remains  limpid  :  it  ac- 
quires a  straw-yellow  tint,  due  to  traces  of  bran  present,  but — 
although  a  peculiar  resin  may  be  dissolved — the  solution  does 
not  possess  a  disagreeable  taste.  When,  on  the  contrary,  darnel 
is  present,  the  alcohol  assumes  a  green  tint,  which  gradually 
deepens,  and  possesses  a  bitter  and  nauseous  taste  ;  the  resi- 
due, left  by  the  evaporation  of  the  tincture  to  dryness,  has  a 
greenish-yellow  color,  and  a  still  more  disagreeable  flavor  than 
the  alcoholic  solution. 

Legumens. — Leguminous  meals  cannot  be  added  otherwise 
than  in  small  proportions  to  wheaten  flour,  owing  to  the  rapid- 
ity Nvith  which  they  change  the  properties  of  the  latter,  and 
communicate  to  it  their  characteristic  odor — noticeable  upon 
treating  the  flour  with  a  little  boiling  water.  Their  presence 
is  also  easily  detected  by  the  distinctive  properties  of  the  veg- 
etable itself,  and  by  the  appearance  of  the  amylaceous  residue 
in  the  microscopic  examination.  In  order  to  decide  as  to  the 
presence  of  legumens,  the  washings  containing  the  starchy  mat- 
ter of  the  flour,  after  the  particles  of  gluten  present  have  been 
separated  by  passing  the  fluid  through  a  silk  sieve,  are  divided 
into  two  portions.  One  portion  is  allowed  to  undergo  fermenta- 
tion, at  a  temperature  of  18°  to  20°  :  in  case  leguminous  sub- 
stances are  not  present,  lactic  fermentation  occurs  and  the 
odor  of  sour  milk  is  alone  perceptible ;  if,  on  the  other  hand, 
legumens  are  contained  in  the  fluid,  rancid  fermentation  takes 
place,  and  an  odor  is  emitted  resembling  that  of  decayed 
cheese.  The  remaining  portion  of  the  washings,  after  being 
decanted  from  the  residue  of  amylaceous  matter,  is  filtered 
and  evaporated  until  a  yellowish  translucent  pellicle  appears 
upon  its  surface.  The  fluid  is  then  again  filtered  from  the 
coagulated  albumen  common  to  all  flours,  and  the  legumin- 


I22  LEGAL  CHEMISTRY. 

ous  substances  present  coagulated  by  the  addition,  drop  by 
drop,  of  acetic  acid. 

The  leguminous  deposit  produced  appears  white  and  flaky ; 
when  examined  under  the  microscope,  it  presents  lamilla  emar- 
ginated  at  the  border  ;  it  is  odorless  and  tasteless  ;  when  dried, 
it  assumes  a  horny  appearance  ;  it  is  insoluble,  both  in  water 
and  alcohol,  and  does  not  become  gelatinous  when  treated 
with  boiling  water ;  it  is  readily  soluble  in  potassa  and  other 
alkaline  solutions,  from  which  it  is  precipitated  upon  ad- 
dition of  nitric,  hydrochloric,  acetic,  oxalic,  and  citric  acids ; 
upon  protracted  boiling  in  water,  it  loses  its  property  of  be- 
ing soluble  in  ammonia.  The  above  tests  having  been  applied, 
the  residue  containing  the  starch  is  next  examined.  For  this 
purpose,  a  small  portion  is  moistened  with  a  little  water,  a  few 
drops  of  iodine  solution  added,  and  the  mixture  placed  on  the 
side  of  the  microscope :  the  bluish  grains  contained  in  the 
polyhedral  and  cellular  envelope  (Fig.  15) 
are  easily  recognized.  The  mixture 
on  the  glass  may  also  be  treated  with  an 
aqueous  solution  of  potassa  (containing 
10  per  cent,  of  the  salt),  or  with  dilute  hy- 
drochloric acid  :  these  reagents  dissolve 
the  starch  present,  leaving  the  reticulated 

Fig.  15. 

tissue  intact.  Should  this  examination 
fail  to  give  a  definite  result,  the  remaining  portion  of  the 
amylaceous  residue  is  subjected  to  a  sort  of  levigation,  and 
the  part  most  slowly  deposited  separated.  In  this  portion 
the  reticulated  tissues  of  the  leguminous  substances  present 
are  contained,  and,  as  they  are  comparatively  free  from  foreign 
matters,  their  identification  is  a  matter  of  comparative  ease. 
In  case  the  presence  of  reticulated  tissue  is  indicated,  it  is 
still  necessary  to  apply  confirmatory  chemical  tests. 


FLOUR  AND  BREAD. 


13-3 


Meals  prepared  from  beans,  horse-beans,  and  lentils,  con- 
tain a  tannin  which  imparts  a  green  or  black  color  to  salts  of 
iron.  The  coloration  is  rendered  very  sensitive  if  a  rather  con- 
siderable quantity  of  the  flour  to  be  examined  is  passed  through 
a  silk  sieve,  and  the  remaining  bran  treated  with  a  solution  of 
sulphate  of  iron  (Jerrico-ferrous  sulphate)  :  the  reaction  imme- 
diately occurs,  even  if  the  sample  contains  but  10  per  cent,  of 
bean  meal.  The  meals  of  horse-beans  and  of  vetches  acquire 
a  red  color,  when  exposed  to  the  successive  action  of  nitric  acid 
and  of  ammonia  vapors.  In  order  to  apply  this  test,  the  sus- 
pected flour  is  placed  upon  the  edge  of  a  capsule  containing 
nitric  acid,  the  latter  heated,  and,  as  a  yellow  coloration  ap- 
pears, the  acid  removed  and  replaced  by  ammonia.  The  cap- 
sule is  then  set  aside  :  if  the  flour  is  adulterated  with  either  of 
the  above  vegetables,  reddish  spots,  which  are  easily  percepti- 
ble by  aid  of  a  magnifying  glass,  are  soon  produced. 

In  case  bread  is  to  be  examined,  it  is  exhausted  with  water, 
the  fluid  passed  through  a  sieve,  the  upper  layer  decanted, 
then  evaporated,  and  the  residue  taken  up  with  alcohol.  The 
tincture  so  obtained  is  evaporated,  and  the  second  residuum 
treated  with  nitric  acid  and  ammonia,  as  directed  above. 
When  meals  prepared  from  beans,  vetches,  or  lentils  are  heated 
on  a  water-bath  with  hydrochloric  acid,  diluted  with  three  to 
four  times  its  volume  of  water,  a  cellular  tissue,  possessing  the 
color  of  wine-dregs,  remains  behind  ;  flours  of  wheat,  peas,  and 
kidney-beans  leave  a  colorless  residue,  when  subjected  to  the 
same  treatment. 

Finally  ;  the  grains  of  the  starch  (Jeatla)  of  legumens  pos- 
sess a  volume  about  equal  to  that  of  potato  granules,  and 
exhibit  either  a  longitudinal  furrow  in  the  direction  of  their 
longer  axis,  or  a  double  furrow  arranged  in  a  star-like  form. 


124  LEGAL  CHEMISTRY. 

c.  EXAMINATION  OF  THE  ASH. 

Leguminous  substances,  and  more  particularly  mineral 
salts,  are  detected  by  the  examination  of  the  ash  left  upon 
the  incineration  of  the  flour. 

Detection  of  Legumens. — Pure  wheaten  flour  furnishes  an 
ash  consisting  of  about  2  per  cent,  of  its  weight ;  whereas  meals 
of  legumens  leave  from  3  to  4  per  cent,  of  their  weight  in  ash. 
This  difference  is,  however,  too  slight  to  furnish  conclusive 
results;  the  analysis  of  the  ash  is  also  necessary.  The  ash 
of  wheaten  flour  is  non-deliquescent,  dry,  semi-fused,  and  chief- 
ly consists  of  phosphates  of  potassa,  soda,  magnesia  and  lime, 
of  sulphates,  and  of  silica.  The  solution  obtained  by  treating  the 
ash  with  water  has  an  alkaline  reaction.  The  phosphates  of 
the  alkalies,  present  in  the  ash  of  wheat,  exist  in  the  state 
of  pyrophosphates,  and,  as  chlorides  are  absent,  the  addition  of 
nitrate  of  silver  to  the  aqueous  solution  of  the  ash  produces 
a  white  precipitate,  consisting  entirely  of  pyrophosphate  of 
silver,  which  is  not  affected  by  exposure  to  the  light. 

The  ash  of  leguminous  meals  is  deliquescent  and  soluble 
in  water,  forming  a  strongly  alkaline  solution,  which  con- 
tains both  chlorides  and  neutral  phosphates.  The  latter 
give  a  clear  yellow  precipitate  with  nitrate  of  silver.  Upon 
adding  a  solution  of  this  salt  to  the  aqueous  solution  of  the 
ash,  a  pale  yellow  precipitate,  which  turns  violet  if  exposed 
to  the  light,  is  therefore  produced. 

Detection  of  mineral  substances. — The  principal  mineral  sub- 
stances, that  are  fraudulently  added  to  flour,  are  ground  cal- 
cined bones,  sand,  lime,  plaster,  alum,  and  sulphate  of  copper. 
The  two  last  named  salts  are  almost  invariably  added  in  small 
quantities ;  alum  renders  the  flour  white,  even  when  used  in 
the  proportion  of  one  per  cent. ;  sulphate  of  copper  is  added 


FLOUR  AND  BREAD. 


I25 


to  impart  a  good  appearance  to  bread  made  from  a  damaged 
flour. 

a.  Ground  bones  (carbonate  and  phosphate  of  lime). — The 
washings  of  the  gluten  are  placed  in  a  conical  vessel,  and,  after 
some  time  has  elapsed,  the  clear  supernatant  fluid  is  removed 
by  means  of  a  syphon,  a  conical  shaped  deposit  remaining  on 
the  bottom  of  the  vessel  :  two  hours  later,  the  fresh  layer  of 
fluid  that  has  formed  is  removed  with  a  pipette.     As  soon  as 
the  residue  becomes  nearly  solid,  it  is  detached  from  the  ves- 
sel, placed  upon  a  fragment  of  plaster,  and   allowed  to  dry. 
The  bones,  being  heavier  than  the  amylaceous  substances,  are 
to  be  found  in  the  apex  of  the  cone  formed  by  the  residue. 
This  is  detached,  and  incinerated :  in  case  the  ash  obtained 
contains  phosphate    and   carbonate   of   lime,  the  addition  of 
hydrochloric  acid  will  cause  effervescence,  and,  upon  adding 
ammonia  to  the  acid  solution,  a  white  precipitate  will  be  form- 
ed.    If  the  solution  is  then  filtered  and  oxalate  of  ammonia 
added  to  the  filtrate,  a  precipitate  will  be  produced  which, 
when  heated  to  redness,  leaves  a  residue  of  caustic  lime  pos- 
sessing an  alkaline  reaction. 

b.  Sand. — As  this  substance  possesses  a  much  greater  specific 
gravity  than  the  usual  constituents  of  flour,  it  is  only  necessary, 
in  order  to  accomplish  its  separation,  to  repeatedly  stir  the 
flour  with  water,  and  remove  the  deposit  at  first  formed,  which, 
if  consisting  of  sand,  will  be  insoluble  in  acids,  and  will  grate, 
when  placed  between  the  teeth. 

c.  Carbonates  of  lime  aud  magnesia;  vegetable  ashes. — Car- 
bonic acid  is    always  evolved,  upon  treating  flour  with  hydro- 
chloric acid.  If  the  base  present  be  calcium,  upon  adding  oxa- 
late of  ammonia  to  the  filtered  solution — which  has  previously 
been  neutralized  with  ammonia — a  white  precipitate,  possess- 
ing the  properties  mentioned  above,  will  be  formed ;  in  case 


i26  LEGAL  CHEMISTRY. 

the  base  is  magnesia,  the  addition  of  oxalate  of  ammonia  will 
fail  to  cause  a  precipitate,  but  upon  adding  solution  of 
phosphate  of  ammonia  to  the  fluid  a  granular  precipitate  of 
phosphate  of  ammonia  and  magnesia  is  produced ;  if,  finally, 
the  flour  contains  vegetable  ashes — i.  e.  carbonates  of  the  al- 
kalies— bichloride  of  platinum  will  produce  in  the  acid  solution 
a  yellow  precipitate  :  the  addition  of  vegetable  ashes,  moreover, 
would  render  the  ash  of  the  flour  deliquescent  and  very  strong- 
ly alkaline. 

d.  Lime. — In  presence  of  lime,  carbonic  acid  produces  a 
white  precipitate,  when  conducted  into  the  filtered  aqueous 
extract  of  the  flour. 

e.  Plaster. — The  flour  is  boiled  with  water  acidulated  with 
hydrochloric  acid,  the  fluid  filtered,  and  lime  detected  in  the  fil- 
trate by  means  of  ammonia  and  oxalate  of  ammonia.      The 
presence  of  sulphuric  acid  is  indicated  by  the  formation  of  a 
precipitate   insoluble  in  acids,   upon  addition  of  solution  of 
chloride  of  barium.     Upon  calcining  the  flour  without  access 
of  air,  sulphate  of  lime  is  converted  into  the  corresponding 
sulphide :  the   residue  of  the  calcination,  when  treated  with 
hydrochloric  acid,  evolves  sulphuretted  hydrogen,  and  the  lime 
present  in  the  filtered  acid  solution  is  likewise  precipitated  by 
the  addition  of  ammonia  and  oxalate  of  ammonia. 

f.  Alum  — A  portion  of  the  flour  to  be  examined  is  treated 
with  water,  the  fluid  filtered,  and  the  filtrate  divided  in  two 
portions :  in  one,  sulphuric  acid  is  detected  by  means  of  chlo- 
ride of  barium  ;  in  the  other,  alumina  by  adding  a  solution  of 
potassa,  which  gives  with  its  salts  a  white  gelatinous  precipi- 
tate, soluble  in  an  excess  of  the  reagent.* 

*  If  the  detection  of  alum  in  bread  is  desired,  a  portion  of  the  crumb 
is  incinerated  in  a  platinum  dish,  the  ash  is  treated  with  concentrated  hy- 
drochloric acid,  the  filtered  solution  evaporated  to  dryness,  and  the  residue 


FLOUR  AND  BREAD. 


127 


g.  Sulphate  of  copper. — About  200  grammes  of  the  bread  under 
examination  are  incinerated  ;  the  ash  treated  with  nitric  acid  ; 
the  mixture  evaporated  until  it  acquires  a  sticky  consistence, 
and  the  mass  then  taken  up  with  water.  The  aqueous  solu- 
tion is  next  filtered  ;  an  excess  of  ammonia  and  several  drops 
of  solution  of  carbonate  of  ammonia  added  ;  the  fluid  again 
filtered,  the  filtrate  slightly  acidulated  with  nitric  acid,  arid 
divided  into  two  parts.  It  is  then  ascertained  if  sulphuretted 
hydrogen  produces  in  one  portion  of  the  solution  a  brown 
precipitate  of  sulphide  of  copper,  and  if  solution  of  ferrocyanide 
of  potassium  produces  in  the  other  a  reddish-brown  precipi- 
tate of  ferrocyanide  of  copper.* 

treated  with  hydrochloric  acid,  which  now  leaves  the  silica  present  undis- 
solved.  The  acid  solution  is  then  filtered,  nearly  neutralized  with  carbon- 
ate of  soda,  and  an  alcoholic  solution  of  potassa  added  in  excess.  The 
earthy  phosphates  present  are  now  precipitated,  alumina  remaining  in  solu- 
tion. The  use  of  aqueous  potassa  in  this  case — as  well  as  in  the  case  men- 
tioned in  the  text — is  not  advisable,  as  it  is  seldom  entirely  free  from 
alumina.  Upon  slightly  acidulating  the  alkaline  filtrate  with  hydrochloric 
acid,  and  adding  carbonate  of  ammonia,  the  alumina  present  is  precipitated, 
and  may  be  dried  and  tested  by  means  of  the  reaction  with  nitrate  of  co- 
balt before  the  blow-pipe. 

In  the  quantitative  estimation  of  alumina,  the  phosphoric  acid  usually 
present  in  the  precipitate  should  be  removed.  This  is  done  by  dissolving 
the  precipitate  in  nitric  acid  and  immersing  a  piece  of  metallic  tin  in  the 
boiling  solution  :  phosphoric  acid  is  thrown  down  as  a  mixture  of  stannic 
oxide  and  phosphate,  and  the  alumina  is  then  precipitated  as  usual  by 
carbonate  of  ammonia. —  Trans. 

*  According  to  Wagner,  if  the  ash,  obtained  by  incinerating  the  adul- 
terated bread,  is  washed  with  water,  shining  spangles  of  metallic  copper 
are  separated. — Trans. 


I28  LEGAL  CHEMISTRY. 

FIXED    OILS. 

Olive  oil  designed  for  table  use  is  frequently  adulterated 
with  the  oils  of  poppy,  sesame,  cotton-seed,  pea-nuts,  and 
other  nuts  ;  olive  oil,  intended  for  manufacturing  purposes, 
is  often  mixed  with  colza  and  nut  oils. 

The  tests  used  are  of  a  rather  unsatisfactory  character. 
In  all  instances,  when  the  chemist  is  called  upon  to  pro- 
nounce as  to  the  adulteration  of  an  oil,  it  is  necessary  to 
execute  comparative  experiments  with  the  pure  oil,  and  with 
admixtures  arbitrarily  prepared  :  it  is  only  when  this  is 
done  that  the  indications  obtained  are  of  value. 

EXAMINATION    OF    OLIVE   OIL   INTENDED    FOR    TABLE    USE. 

a.  The  density  of  the  oil  is  determined  by  means  of  a 
hydrometer  (oleometer)  provided  with  a  scale  giving  the  den- 
sities from  0.8  to  0.94,  for  the  temperature  of  15.°    Pure  olive 
oil  possesses  a  specific  gravity  of  0.917;  poppy  oil  one  of 
0.925  ;  a  mixture  of  the  two,  an  intermediate  density.      Since 
the  fixed  oils  are  not  definite  chemical  compounds,  this  test  is 
seldom  conclusive. 

b.  Two  or  three  cubic  centimetres  of  concentrated  nitric 
acid,  containing  nitric  peroxide  in  solution  (or  a  solution  of 
mercury  in  strong  nitric  acid),  are  added  to  the  oil  to  be  ex- 
amined, as  well  as  to  a  sample  of  pure  olive  oil.     The  two 
samples  are  then  allowed  to  stand  in  a  room  where  the  tem- 
perature does  not  exceed  io.°     The  oleine  of  the  olive  oil  is 
converted  into  solid  elaidine,  and  the  mixture  after  some  time 
becomes  sufficiently  thick  to  remain  in  the  vessel  upon  inver- 
sion.    If  the  sample  under  examination  is  free  from  adultera- 
tion, it  will  solidify  at  the  same  time  as  the  pure  oil ;  whereas, 
the  presence  of  one  per  cent,  of  poppy  oil,  or  of  other  drying 
oils,  suffices  to  retard  the  solidification  for  forty  minutes. 


FIXED  OILS.  I29 

c.  Fifteen  grammes  of  the  oil  are  mixed  in  a  glass  vessel 
with  the  same  amount  of  strong  sulphuric  acid,  the  tempera- 
ture of  the  two  liquids  being  previously  observed.     The  mix- 
ture is  stirred  with  a  thermometer,  and  the  maximum  tempera- 
ture noted  :  pure  olive  oil  produces  an  elevation  of  temperature 
°f    37-°7  >  Pure  P°PPy    oil,  an   elevation    of    70. °5  ;  and  a 
mixture  of  the  two  an  elevation  of  temperature  intermediate 
between  37. "7  and  7o.°5. 

d.  One  volume  of  nitric  acid  of  sp.  gr.   1.33  is  agitated 
with  5  grammes  of  the  oil,  and  notice  taken  of  the  coloration 
produced  after  the  lapse  of  five  minutes.     If  the  olive  oil  is 
pure,  it  acquires  a  pale  green  color ;  in  case  it  is  mixed  with 
sesame  or  nut  oil,  a  deep-red  color  appears  :  poppy  oil  also 
communicates  a  reddish  coloration,  but  one  less  deep  than  the 
preceding. 

If  an  acid  of  sp.  gr.  1.22  is  taken,  it  is  still  less  difficult 
to  distinguish  between  sesame,  nut  and  poppy  oils ;  the  latter 
assumes,  in  this  case,  a  pale  yellowish-red  color. 

Pea-nut  oil  fails  to  exhibit  a  coloration ;  but  can  be 
recognized  by  its  conversion  into  a  white  solid,  when  mixed 
with  \  of  its  volume  of  a  solution  of  caustic  soda  of  sp.  gr. 

1-34- 

EXAMINATION   OF  OLIVE   OIL    INTENDED   FOR   MANUFACTURING 
PURPOSES. 

The  chief  adulterations  are  colza  and  nut  oils.  The  latter 
is  detected  by  means  of  the  reaction  with  nitric  acid,  as  de- 
scribed above.  Colza  oil  is  recognized  by  mixing  5  volumes  of 
the  sample  to  be  examined,  with  i  volume  of  sulphuric  acid 
of  sp.  gr.  1.655  :  if  colza  or  nut  oils  are  present,  a  brown 
coloration  ensues ;  under  the  same  circumstances,  pure  olive 

6* 


130  LEGAL  CHEMISTRY. 

oil  assumes  a  pale  greenish  hue.  In  case  the  sample  ac- 
quires a  brown  color  when  treated  with  sulphuric  acid,  and 
a  red  coloration  is  produced  by  the  addition  of  nitric  acid,  it 
contains  nut  oil ;  if  sulphuric  acid  produces  a  brown  colora- 
tion, and  nitric  acid  fails  to  change  it,  the  presence  of  oil  of 
colza  is  indicated. 

EXAMINATION    OF    HEMPSEED    OIL. 

This  oil  is  frequently  adulterated  with  linseed  oil.  The 
reactions  exhibited  by  these  oils  are  neatly  identical,  and  the 
detection  of  the  admixture  is  extremely  difficult.  It  is  advis- 
able to  mix  the  suspected  oil  with  sulphuric  acid,  notice  bein  g 
taken  of  the  elevation  of  temperature  produced,  and  to  treat 
it  with  nitric  acid  and  with  dilute  potassa  solution,  subjecting, 
at  the  same  time,  an  artificial  mixture  of  the  two  pure  oils 
to  the  same  treatment,  and  comparing  the  results  obtained. 

TEA  AND  ITS  ADULTERATION. 

Among  alimentary  substances  probably  no  article  is 
subjected  to  more  adulteration  than  tea.  The  sophistica- 
tions practised  may  be  conveniently  divided  into  three 
classes: 

1.  Additions  made  for  the  purpose  of  giving  increased 
bulk  and   weight,  which   include  foreign  leaves   and   ex- 
hausted tea-leaves,  and  also  certain  mineral   substances, 
such  as  metallic  iron,  sand,  brick-dust,  etc. 

2.  Substances  added  in  order  to  produce  an  artificial 
appearance  of  strength  in  the  tea  decoction,  catechu,  or 
other  bodies  rich  in  tannin,  and  iron  salts  being  chiefly 
resorted  to  for  this  purpose. 

3.  The  imparting  of  a  bright  and  shining  appearance  to, 
the  tea  by  means  of  various  coloring  mixtures  or  "  facings," 


TEA  AND  ITS  ADULTERA  TION. 


which  adulteration,  while  sometimes  practised  upon  black 
tea,  is  much  more  common  with  the  green  variety.  This 
sophistication  involves  the  use  of  steatite  (soap-stone), 
sulphate  of  lime,  China  clay,  Prussian  blue,  indigo,  tur- 
meric, and  graphite ;  chromate  of  lead  and  copper  salts 
being  but  very  rarely  employed.  The  compound  most 
frequently  used  consists  of  a  mixture  of  soap-stone  (or 
gypsum)  with  Prussian  blue,  to  which  a  little  turmeric  is 
sometimes  added. 

Genuine  tea  is  the  prepared  leaf  of  Thea 
sinensis.  It  contains:  moisture,  6$  to  10$; 
theine,  0.4$  to  4.0$;  tannin,  (green)  20$, 
(black)  10$;  ash,  5$  to  6$;  soluble  extrac- 
tive matters,  32$  to  50$  ;  and  insoluble  leaf, 
47$  to  54$. 

The  presence  of  foreign  leaves,  and,  in  some 
instances,  of  mineral  adulterants,  in  tea  is 
best  detected  by  means  of  a  microscopic  ex- 
amination of  the  suspected  sample.  The  genu- 
ine tea-leaf  is  characterized  by  its  peculiar 
serrations  and  venations.  Its  border  exhibits 
serrations  which  stop  a  little  short  of  the 
stalk,  while  the  venations  extend  from  the 
central  rib,  nearly  parallel  to  one  another, 
but  turn  just  before  reaching  the  border  of  the  leaf  (see 
Fig.  16).  The  Chinese  are  said  to  employ  ash,  plum,  ca- 
mellia, velonia,  and  dog-rose  leaves  for  admixture  with  tea, 
and  the  product  is  stated  to  be  often  subjected  in  England 
to  the  addition  of  the  leaves  of  willow,  sloe,  beech,  haw- 
thorn, elm,  box-poplar,  horse-chestnut,  and  fancy  oak  (see 
Figs.  17,  18,  and  19).  For  scenting  purposes  chulan  flow- 
ers, rose,  jasmine,  and  orange  leaves  are  frequently  em- 


132 


LEGAL  CHEMISTRY. 


ployed.  In  the  microscopic  examination  the  sample  should 
be  moistened  with  hot  water,  spread  out  upon  a  glass  plate, 
and  then  submitted  to  a  careful  inspection,  especial  atten- 
tion being  given  to  the  general  outline  of  the  leaf  and  its 
serrations  and  venations.  Most  foreign  leaves  will,  in  this 
way,  be  identified  by  their  botanical  character.  The  pres- 


Fig.17 


Fig. 19 


WILLOW 


BEECH 


ence  of  exhausted  tea-leaves  may  also  often  be  detected  by 
their  soft  and  disintegrated  appearance.  If  a  considerable 
quantity  of  the  tea  be  placed  in  a  long  glass  cylinder  and 
agitated  with  water,  the  coloring  and  other  abnormal  bodies 
present  frequently  become  detached,  and  either  rise  to  the 
surface  of  the  liquid  as  a  sort  of  scum  or  fall  to  the  bottom 
as  a  deposit.  In  this  way  Prussian  blue,  indigo,  soap-stone, 


TEA  AND  ITS  AD  UL  TERA  TION.  133 

gypsum,  sand,  and  turmeric  can  sometimes  be  separated 
and  subsequently  recognized  by  their  characteristic  micro- 
scopic appearance.  The  separated  substances  should  also 
be  chemically  tested.  Prussian  blue  is  detected  by  heat- 
ing with  a  solution  of  caustic  soda,  filtering,  and  acidu- 
lating the  filtrate  with  acid,  and  then  adding  chloride  of 
iron,  when,  in  its  presence,  a  blue  color  will  be  produced. 
Indigo  is  best  discovered  by  its  appearance  under  the 
microscope  ;  it  is  not  decolorized  by  caustic  alkali,  but  it 
dissolves  in  sulphuric  acid  to  a  blue  liquid.  Soap-stone, 
gypsum,  sand,  metallic  iron,  etc.,  are  identified  by  means  of 
the  usual  chemical  tests.  A  compound,  very  aptly  termed 
"Lie-tea,"  is  often  met  with.  It  forms  little  pellets  con- 
sisting of  tea-dust  mixed  with  foreign  leaves,  sand,  etc., 
and  held  together  by  means  of  gum  or  starch.  This,  when 
treated  with  boiling  water,  falls  to  powder.  In  the  presence 
of  catechu  the  tea  infusion  usually  becomes  muddy  upon 
cooling;  in  case  iron  salts  have  been  employed  to  deepen 
the  color  of  the  liquor,  they  can  be  detected  by  treating 
the  ground  tea-leaves  with  acetic  acid  and  testing  the  solu- 
tion with  ferrocyanide  of  potassium.  Tea  should  not  turn 
black  upon  immersion  in  hydrosulphuric  acid  water,  nor 
should  it  impart  a  blue  color  to  ammonia  solution.  The 
infusion  should  be  amber-colored,  and  not  become  red- 
dened by  the  addition  of  an  acid. 

TEA   ASSAY. 

In  the  following  tea  assay  proper  the  estimation  of  theine 
is  not  included.  The  processes  suggested  for  this  determi- 
nation are  rather  unsatisfactory;  and  there  appears,  more- 
over, to  exist  no  direct  relation  between  the  quality  of  tea 
and  the  proportion  of  theine  contained.  The  tests  here 


134  LEGAL  CHEMISTRY. 

mentioned,  in  connection  with  tjiose  already  given,  will, 
it  is  believed,  usually  suffice  to  indicate  to  the  analyst  the 
presence  of  spent  leaves,  inorganic  coloring  matters,  and 
other  mineral  adulterations. 

TANNIN. — A  good  process  for  the  estimation  of  tannin  in 
tea  has  been  published  by  Allen  (Chem.  News,  vol.  xxix. 
p.  169  et  seq.)  A  standard  solution  of  lead  acetate  is  pre- 
pared by  dissolving  5  grammes  of  the  salt  in  distilled  water 
and  diluting  the  liquid  to  1,000  c.c.  As  an  indicator,  5 
milligrammes  of  potassic  ferricyanide  are  dissolved  in  5  c.c. 
of  water,  and  an  equal  volume  of  strong  ammonia-water 
added.  The  exact  strength  of  the  lead  solution  is  to  be 
determined  by  means  of  a  solution  of  pure  tannin  of  known 
strength.  Two  grammes  of  the  tea  to  be  tested  are  pow- 
dered, boiled  with  water,  and,  after  filtering  and  thorough 
washing,  the  decoction  is  made  up  to  a  volume  of  250  c.c.; 
10  c.c.  of  the  lead  solution  are  now  diluted  with  90  c.c. 
of  boiling  water,  and  the  tea  infusion  is  gradually  added 
from  a  burette  until  a  few  drops  of  the  liquid,  when  filtered 
and  added  to  a  little  of  the  indicator  placed  upon  a  porce- 
lain slab,  causes  a  pink  coloration  to  appear;  125,  divided 
by  the  number  of  c.c.  of  tea  infusion  found  to  be  necessary 
to  produce  the  pink  color,  will  give  directly  the  percentage 
of  tannin  in  the  sample  examined.  As  previously  stated, 
green  tea  contains  20$  of  tannin,  and  black  tea  10$.  In 
spent  tea,  however,  only  about  2%  of  tannin  is  present; 
and,  although  any  tea  deficient  in  this  constituent  could 
be  fortified  by  the  addition  of  catechu,  its  determination 
often  affords  indications  of  value. 

THE  ASH — a.  Total  Ash- — 5  grammes  of  the  sample  are 
placed  in  a  platinum  vessel  and  heated  over  a  Bunsen 
burner  until  complete  incineration  has  been  accomplished. 


TEA  AND  ITS  ADULTERATION".  135 

The  vessel  is  allowed  to  cool  in  a  desiccator,  and  is  then 
weighed  as  quickly  as  possible.  In  genuine  tea  the  total 
ash  should  not  be  much  below  5$  or  much  above  6$,  and 
it  should  not  be  magnetic ;  in  "  faced  "  teas  the  propor- 
tion of  total  ash  is  often  10$  or  15$  ;  in  "  lie-tea  "  it  may 
reach  30$,  and  in  spent  leaves  it  may  fall  as  low  as  3$,  the 
ash  in  this  case  being  abnormally  rich  in  lime  salts  and 
poor  in  potash  salts.  Tea-dust  sometimes  contains  10$  of 
total  ash  without  necessarily  being  considered  bad  in  quality. 
In  the. proposed  United  States  tea-adulteration  law  (1884) 
a  maximum  of  8$  of  total  ash  is  allowed  for  tea-leaf. 

b.  Ash  insoluble  in  water. — The  total  ash  obtained  in  a 
is  washed  into  a  beaker  and  boiled  with  water  for  a  con- 
siderable time.     It  is  then  brought  upon  a  filter  and  the 
insoluble  residue  washed,  dried,  ignited,  and  weighed.     In 
unadulterated  tea   it    will  not  exceed  3$  of  the   sample 
taken. 

c.  Ash  soluble  in  water. — This  proportion  is  obtained  by 
deducting   ash   insoluble    in   water    from    the    total    ash. 
Genuine  tea  contains  from  3$  to  3.5$  of  soluble  ash,  or  at 
least  50$  of  the  total  ash,  whereas  in  spent  or  exhausted 
tea  the  amount  is  often  but  0.5$. 

d.  Ash  insoluble  in  acid. — The  ash  insoluble  in  water  is 
boiled  with  dilute  hydrochloric  acid  and  the  residue  sepa- 
rated by  filtration,  washed,  ignited,  and  weighed.     In  pure 
tea  the  remaining  ash  ranges  between  0.3$  and  0.8$  ;  in 
"  faced  "  teas,  or  in  teas  adulterated  by   the  addition  of 
sand,  etc.,  it  may  reach  the  proportion  of  2%  to  5$.     Frag- 
ments of  silica  and  brick-dust  are  occasionally  to  be  found 
in  the  ash  insoluble  in  acid. 

TH-E  EXTRACT.^-TWO  grammes  of  the  carefully-sampled 
tea  are  boiled  with  water  until  all  soluble  matter  is  dissolved, 


136  LEGAL  CHEMISTRY. 

water  being  added  from  time  to  time  to  prevent  the  solution 
becoming  too  concentrated.  The  solution  is  poured  upon 
a  tared  filter,  and  the  remaining  insoluble  leaf  repeatedly 
washed  with  hot  water  until  the  filtered  liquid  becomes 
colorless.  The  filtrate  is  now  diluted  to  a  volume  of  200 
c.c.,  and  of  this  50  c.c.  are  taken  and  evaporated  in  a 
weighed  dish  over  the  steam-bath  until  the  weight  of  the 
extract  remains  constant;  its  weight  is  then  determined. 
Genuine  tea  affords  from  32$  to  50$  of  extract,  according 
to  its  age  and  quality  ;  in  spent  tea  the  proportion  of 
extract  will  be  greatly  reduced. 

INSOLUBLE  LEAF. — The  insoluble  leaf  obtained  in  the 
preceding  operation,  together  with  the  weighed  filter,  is 
placed  in  an  air-bath  and  dried  for  at  least  eight  hours  at  a 
temperature  of  110°  C.;  its  weight  is  then  determined.  In 
unadulterated  tea  the  amount  of  insoluble  leaf  ranges  be- 
tween 47$  and  54$ ;  in  exhausted  tea  it  may  reach  a  pro- 
portion of  75$. 

It  should  be  noted  that  in  the  foregoing  estimations  the 
tea  is  taken  in  its  ordinary  air-dried  condition.  If  it  be 
desired  to  reduce  the  results  obtained  to  a  dry  basis,  an 
allowance  for  the  moisture  present  in  the  sample  (an 
average  of  8$),  or  a  direct  determination  of  the  same,  must 
be  made. 

The  following  tabulation  gives  the  constituents  of  genu- 
ine tea  so  far  as  the  ash,  extract,  and  insoluble  leaf  are 
involved  : 

Total  ash — ranges  between  4.7$  and  6.2$. 

Ash  soluble  in  water — ranges  between  3$  and  3.5$ ;  should 
equal  50$  of  total  ash. 

Ash  insoluble  in  water — not  over  2.75$. 

Ash  insoluble  in  acid — ranges  between  0.3$  and  0.8$. 


MILK.  137 

Extract — ranges  between  32$  and  48$. 

Insoluble  leaf — ranges  between  43$  and  58$. 

The  table  below  may  prove  useful  as  indicating  the  re- 
quirements to  be  exacted  when  the  chemist  is  asked  to  give 
an  opinion  concerning  the  presence  of  facing  admixtures 
or  of  exhausted  or  foreign  leaves  in  a  sample  of  tea : 

Total  ash — should  not  be  under  4.5$  or  over  7$. 

Ash  soluble  in  water — should  not  be  under  40$  of  total  ash. 

Ash  insoluble  in  water — should  not  be  over  3$. 

Ash  insoluble  in  acid — should  not  be  over  i$. 

Extract — should  not  be  under  30$. 

Insoluble  leaf — should  not  be  over  60$. 

NOTE, — The  British  Society  of  Public  Analysts  adopt: 
Total  Ash  (dry  basis) — not  over  8$  (at  least  3$  should  be 
soluble  in  water). 

Extract  (tea  as  sold) — not  under  30$. 

MILK. 

The  chief  constituents  of  milk  are  water,  butter,  caseine, 
lactose  (milk-sugar),  traces  ©J:  albumen  and  mineral  salts; 
Butter  is  present  in  the  form  of  minute  globules,  held  in  sus- 
pension j  the  caseine,  for  the  greater  part,  is  in  solution,  only 
a  small  portion  being  present  in  an  insoluble  suspended  con- 
dition. In  milk  only  a  few  days  old,  the  colostrum  (the  milk 
secreted  during  the  first  few  days  after  parturition)  consists 
largely  of  rather  voluminous  cellular  conglomerations,  con- 
taining a  sufficient  quantity  of  albumen  to  coagulate  upon 
heating. 

The  normal  density  of  milk  is  1.030,  water  being  i.ooo; 
the  density  rising  to  1.036,  if  the  fluid  has  been  skimmed. 

Good    milk    contains,  on    an  average,  3.7   per    cent,  of 


138  LEGAL  CHEMISTRY. 

batter;  5.7  per  cent,  of  lactose,  and  leaves  upon  evapora- 
tion 12  to  14  percent,  of  solid  matters.*  The  most  common 
adulteration  of  milk  consists  in  the  addition  of  water.  This 
fraud  is  detected  by  means  of  an  areometer  (lactodensimeter) 
which  gives  directly  the  specific  gravity  of  the  fluid  under 
examination.  Should  the  density  be  much  below  1.030,  it  is 
certain  that  water  has  been  added.  It  does  not,  however, 
necessarily  follow  if  it  is  about  1.030  that  the  milk  is  pure, 
since  the  gravity  of  the  fluid,  which  would  be  increased  upon 
skimming,  could  be  subsequently  reduced  to  1.030  by  the 
addition  of  water.  The  lactodensimeter,  therefore,  although 
useful  in  the  detection  of  a  simple  admixture,  fails  to  give 
reliable  results  if  the  fraud  perpetrated  is  a  double  one  ;  and 
a  determination  of  the  proportion  of  butter  present  is  also 
usually  necessary.  Numerous  methods  have  been  proposed 
to  accomplish  this  estimation.  The  most  preferable  of  these, 
owing  to  the  rapidity  with  which  the  operation  is  executed,  is 
the  use  of  the  lactoscope  (galactoscope).  This  instrument  con- 
sists of  a  tube  provided  with  a  glass  plate  fitted  at  one  end, 
and  with  a  movable  glass  plate  at  the  other  extremity.  A  few 
drops  of  the  milk  to  be  tested  are  placed  between  the  two 
plates,  and  the  tube  lengthened,  by  screwing  out  the  movable 
plate,  until  the  fluid  no  longer  transmits  the  light  of  a  candle 
placed  at  a  distance  of  one  metre.  As  the  opacity  of  milk  is 

*  The  British  Society  of  Public  Analysts   regard  the  following  as  the 
minimum  proportions  of  constituents  in  unadulterated  milk : 

Fat. 2.5  per  cent. 

Solids,  not  fat 9.       "      " 

Total  11.5    "      " 

Water  88.5     "       " 

— Trans. 


MILK.  I39 

due  to  the  butter  present,  it  is  evident  that  the  proportion  of 
this  substance  contained  in  the  sample  can  be  estimated  by 
the  relative  distance  which  the  plates  have  been  separated. 

The  lactoscope  possesses,  however,  but  a  limited  degree  of 
precision.  M.  Marchand  substitutes  to  its  use  the  following 
tests :  A  test-tub^e  is  graduated  in  three  equal  divisions,  the 
upper  one  being  subdivided  into  hundredths  extending  above, 
in  order  to  determine  accurately  the  correct  volume  of  the 
fluid,  expanded,  as  it  is,  by  the  temperature  of  40°,  at  which 
the  examination  is  executed.  The  first  division  of  the  tube  is 
filled  with  milk,  a  drop,  or  two  of  strong  potassa  lye  added, 
and  the  mixtu/e  well  shaken :  the  second  portion  is  then  filled 
with  ether,  and  the  third  with  alcohol.  The  mixture  is  next 
again  thoroughly  agitated,  and  then  exposed  to  a  temperature 
of  40°  in  a  water-bath.  After  standing  for  several  hours,  a 
layer  of  fatty  matter  becomes  sufficiently  separated  to  allow  of 
measurement :  but,  as  it  contains  some  ether  and  as  a  small 
amount  of  butter  may  still  be  retained  in  the  lower  aqueous 
fluid,  a  correction  of  the  results  obtained  is  necessary.  M. 
Marchand  has  compiled  a  table,  which  facilitates  this  correction 
(vide:  Journ.  de  Pharm.,  Novembre  1854,  and  Bulletin  de 
? Academie  de  Medccine,  Paris,  1854.  xix.,  p.  1101). 

Previously  to  the  introduction  of  Marchand's  apparatus, 
use  was  made  of  the  lactometer,  which  consists  simply  of  a  grad- 
uated glass  tube,  in  which  the  suspected  milk  is  allowed  to  re- 
main for  24  hours,  at  a  temperature  of  15°.  After  the  lapse  of 
this  time,  the  cream  present  completely  separates  as  a  super- 
natant layer,  the  thickness  of  which  indicates  the  quality  of  the 
sample  taken. 

M.  Lacomte  recommends  the  addition  of  glacial  acetic  acid, 
in  order  to  cause  the  more  rapid  separation  of  the  cream. 

The  estimation  of  the  butter  being  accomplished,  it  is  fre- 


1 4o  LEGAL  CHEMISTRY. 

quently  needful  to  determine  the  amount  of  lactose  present. 
For  this  purpose,  recourse  is  had  to  Barreswil's  method, 
based  upon  the  reduction  of  cupro-potassic  tartrate  by  milk- 
sugar  in  the  presence  of  alkalies.  A  solution  is  prepared  con- 
taining 40  grammes  of  pure  crystallized  sulphate  of  copper,  600 
or  700  grammes  of  caustic  soda  lye  of  sp.gr.  1.12,  and  1 60  gram- 
mes of  neutral  tartrate  of  potassa.  The  sulphate  of  copper  and 
tartrate  of  potassa  are  previously  dissolved  separately  in  a  little 
water,  the  three  solutions  united,  and  water  added  until  the 
fluid  acquires  a  volume  of  1154.  4  cubic  centimetres.  In  order 
to  standardize  this  test  solution,  a  known  weight  of  pure  lactose 
is  dissolved  in  water  and  the  fluid  added,  drop  by  drop,  from  a 
graduated  burette,  to  a  small  flask  containing  10  cubic  cen- 
timetres of  the  copper  solution,  diluted  with  40  cubic  centime- 
tres of  distilled  water,  and  heated  to  boiling.  At  first  a  yellow 
precipitate  forms,  which  gradually  turns  red,  and  is  deposited 
on  the  bottom  of  the  flask,  leaving  the  solution  colorless.  As 
soon  as  the  test  solution  is  completely  decolorized,  the  addi- 
tion of  the  lactose  solution  is  discontinued,  and  the  weight  of 
lactose  corresponding  to  10  cubic  centimetres  of  the  test  fluid 
calculated  from  the  quantity  used.  The  standard  of  the  test 
solution  having  been  determined,  the  above  operation  is  repeat- 
ed, the  milk  under  examination  being  substituted  for  the  solu- 
tion of  pure  lactose.  The  quantity  of  milk  necessary  to  de- 
colorize 10  cubic  centimetres  of  the  copper  solution  will 
evidently  contain  the  same  amount  of  lactose  as  the  quantity 
of  solution  used  in  the  preliminary  test,  and  the  actual  amount 
of  lactose  present  is  very  easily  calculated.  When  an  estima- 
tion of  the  solid  matter  contained  in  the  milk  is  required,  a 
known  weight  is  evaporated  to  dryness  over  a  water-bath,  and 
the  residue  weighed.  In  performing  this  evaporation,  the  addi- 
tion of  a  known  amount  of  sand,  or  ground  glass,  is  advisable. 


MILK. 


141 


The  amount  of  ash  present  is  determined  by  incinerating  the 
residue  left  by  the  evaporation. 

Foreign  substances  are  sometimes  added  to  milk,  for  the 
purpose  of  disguising  the  presence  of  an  abnormal  quantity  of 
water,  the  principal  of  which  are  :  chalk,  bicarbonate  of  soda, 
emulsion  of  almonds,  gum  tragacanth,  gum  arabic,  starch,  flour, 
decoction  of  barley  or  rice,  sugar,  and  cerebral  substances. 
These  bodies  are  detected  as  follows  : 

Chalk. — If  chalk  is  contained  in  the  milk,  it  readily  sub- 
sides upon  allowing  the  sample  to  remain  at  rest  for  some 
time  in  a  flask,  forming  a  deposit  which  effervesces  when 
heated  with  hydrochloric  acid,  and  dissolves  to  a  solution,  in 
which  the  characteristic  properties  of  a  lime  salt  can  be  recog- 
nized. 

Bicarbonate  of  soda. — In  presence  of  this  compound  the 
milk  possesses  a  strongly  alkaline  reaction,  furnishes  a  serum 
having  a  sharp  and  bitter  taste,  and  leaves  a  residue  of  the 
salt  upon  evaporation. 

Emulsion  of  almonds. — The  milk  has  a  specific  gravity  of 
at  least,  1.033.  If  ^  *s  passed  through  a  gauze,  small  opaque 
lumps  are  separated.  When  examined  under  the  microscope, 
numerous  minute  globules,  having  a  diameter  of  -^\^  of  a  mill- 
imetre, are  observed,  and,  upon  adding  a  few  centigrammes  of 
amygdaline  to  one  or  two  grammes  of  the  milk,  the  character- 
istic odor  of  bitter  almonds  is  produced. 

Gum  tragacantJi. — When  shaken  in  a  glass  flask  and  al- 
lowed to  rest,  the  milk  deposits  on  the  sides  small  transparent 
lumps,  which  usually  present  a  slightly  elongated  or  angular 
form. 

Gum  arabic. — The  addition  of  alcohol  produces  an  abun- 
dant white  opaque  precipitate. 

Starch,  flour,  decoction  of  barley,  rice,  etc. — Upon  boiling  the 


142  LEGAL  CHEMISTRY. 

suspected  milk,  and  adding  tincture  of  iodine,  the  amylaceous 
substances  present  produce  a  blue  coloration  in  the  fluid. 

Sugar. — If  yeast  is  added,  and  the  mixture  allowed  to 
stand  for  some  time  at  a  temperature  of  30°,  alcoholic  fermen- 
tation ensues  ;  under  these  circumstances,  lactose  does  not 
undergo  fermentation. 

Cerebral  •rwfo/dTZ^.— Adulteration  by  these  substances  is 
probably  of  much  less  frequent  occurrence  than  was  formerly 
supposed.  The  admixture  is  detected  by  evaporating  the  milk 
to  dryness,  dissolving  the  residue  in  ether,  evaporating  the 
etherial  solution,  and  fusing  the  second  residue,  which  con- 
sists of  fatty  matters,  with  nitrate  of  potassa  in  a  platinum 
crucible.  The  mass  is  then  taken  up  with  water,  and  chloride 
of  barium  added  to  the  solution.  If  cerebral  substances  were 
contained  in  the  milk,  ether  will  dissolve  the  fatty  matters 
present,  the  phosphorus  of  which  is  converted  into  a  soluble 
phosphate  by  the  calcination  with  nitrate  of  potassa  and  is 
thrown  clown  as  a  white  precipitate,  upon  the  addition  of  a  solu- 
tion of  chloride  of  barium.  This  test  may  be  confirmed  by  a 
microscopic  examination  of  the  milk,  when  the  peculiar  ap- 
pearance of  cerebral  matter  will  be  detected.* 

WINE. 

The  most  common  adulteration  to  which  wines  are  sub- 
jected is  the  addition  of  water  :  wines  having  a  rich  color  are 
frequently  mixed  by  the  dealer  with  lighter  wines,  and  the 
fraud  consummated  by  adding  water.  The  detection  of  this 
adulteration  is  somewhat  difficult,  as  water  is  a  normal  con- 
stituent of  wine.  In  Paris  the  following  method  is  usually 
employed :  As  soon  as  the  wine  is  confiscated,  it  is  ascer- 

*  Fragments  of  nerves,  and  other  organic  structures,  are  frequently  ob- 
served in  this  examination. — Trans. 


WINE.  I43 

tained  what  kinds  of  wine  are  manufactured  by  the  inculpatad 
dealer,  and  a  statement  obtained  from  him,  giving  the  propor- 
tions of  alcohol,  etc.,  contained  in  the  various  brands.  A  wine 
is  then  prepared,  according  to  the  information  received,  an  es- 
timation of  the  alcohol  contained  in  the  prepared  sample  made, 
and  the  results  compared  with  those  furnished  by  a  similar  ex- 
amination of  the  suspected  wine.  In  case  the  proportion  of 
alcohol  is  less  in  the  suspected  wine  than  in  the  prepared 
sample,  it  is  evident  that  a  fraudulent  adulteration  has  been 
committed.  If,  however,  the  quantity  of  alcohol  is  the  same 
in  both  wines,  it  does  not  necessarily  follow  that  the  wine  has 
escaped  admixture,  since  this  body  may  have  been  added  af- 
ter the  adulteration  with  water.  In  addition  to  the  estimation 
of  alcohol,  it  is  also  necessary  to  determine  the  amount  of 
cream  of  tartar  (bitartrate  of  potassa)  present,  as  the  pro- 
portion of  this  salt  would  be  sensibly  decreased  by  the  addi- 
tion of  alcohol  and  water  to  the  wine.  This  fraud  could, 
however,  be  disguised  by  subsequently  adding  the  proper 
amount  of  cream  of  tartar. 

It  is  also  well  to  ascertain  if  two  equal  quantities  of  the 
prepared  sample  and  the  wine  under  examination  require  the 
same  amount  of  solution  of  hypochlorite  of  lime  for  decol- 
orization.  In  case  the  suspected  wine  has  been  adulterated, 
the  quantity  of  hypochlorite  solution  used  will  be  less  than 
the  amount  necessary  to  decolorize  the  prepared  wine.  For- 
eign coloring  matter  may  be  added  by  the  adulterator,  but 
this  fraud  is  easily  detected  by  adding  potassa  to  the  sample  : 
if  its  coloration  is  natural,  a  green  tint  is  produced  ;  whereas, 
if  foreign  matter  has  been  introduced,  the  wine  assumes  va- 
rious other  colors  upon  the  addition  of  the  alkali.* 

*  Cotlini   (Ann.  du  genie  civil,  No.  3,  1873)  states  that  the  following 


144  LEGAL  CHEMISTRY. 

+ 

The  indications  furnished  by  the  above  test  are  rendered 
valueless,  if  the  wine  has  been  artificially  colored  by  the  addi- 
tion of  the  coloring  matter  of  grape-skins  ;  but  the  execution 
of  this  fraud  would  require  some  knowledge  of  chemistry, 
and  fortunately  adulterators,  as  a  class,  are  deficient  in  this 
branch  of  science. 

Another  method  for  detecting  the  addition  of  water  is 
based  upon  the  fact  that  fermented  liquors  do  not  contain  air 
in  solution,  but  only  carbonic  acid  ;  whereas,  water  dissolves 
oxygen  and  nitrogen.  It  is  executed  as  follows  : 

The  wine  to  be  tested  is  placed  in  a  flask,  the  delivery- 
tube  of  which  is  also  filled,  and  heated  ;  the  evolved  gas  be- 
ing collected  in  a  tube  filled  with  mercury.  In  case  the 
wine  is  pure,  the  disengaged  gas  will  be  completely  absorbed 
by  potassa  ;  if,  on  the  other  hand,  water  has  been  added,  an 
unabsorbed  residue,  consisting  of  oxygen  and  nitrogen,  will 
remain. 

This  test  is  useless  in  case  water,  through  which  a  current 
of  carbonic  acid  gas  has  been  passed  for  a  considerable  time, 
has  been  employed.  Under  these  circumstances,  however,  the 
presence  of  the  gas  would  probably  be  detected  by  the  taste 


reactions  occur  when  artificially  colored  wines  are  heated  with  potassa  : 

Pure  wine  no  precipitate  greenish  hue- 

Elderberry  violet  " 

Beet-sugar  red  " 

Logwood  red          violet-red  " 

Privet  violet-blue  " 

Turmeric  light-blue  " 

According  to  M.  de  Cherville  (Qitar.  Jour.  Sc.),  a  bright  violet  colora- 
tion is  produced  in  the  above  test,  if  litmus  be  present. 

Fuchsin  is  separated  by  treatment  with  subacetate  of  lead  and  addition 
of  amylic  alcohol  (Jour,  de  PA-  et  de  Ch.  Mar.  1873). — Trans. 


WINE.  145 

of  the  wine,  as  well  as  by  the  estimation  just  mentioned,  since 
the  sample  would  invariably  contain  a  larger  proportion  of  the 
gas  than  the  standard  with  which  it  is  compared ;  indeed,  it 
would  be  almost  impossible  to  prepare  a  solution  which  con- 
tained exactly  the  proportion  of  carbonic  acid  ordinarily 
present  in  wine. 

It  remains  to  mention  the  methods  employed  in  determin- 
ing the  amount  of  alcohol  and  cream  of  tartar  contained  in 
wine. 

The  alcometrical  method  usually  employed  is  based  upon 
the  difference  in  density  possessed  by  pure  alcohol  and  by 
mixtures  of  alcohol  and  water.  Gay-Lussac  has  proposed  an 
areometer  (alcoometer),  provided  with  a  scale  which  directly 
indicates  the  proportion  of  alcohol  contained  in  a  mixture. 
As  the  indications  furnished  by  this  instrument  vary  with  the 
temperature,  and  the  scale  is  constructed  on  the  basis  of 
a  temperature  of  15°,  a  correction  of  the  results  obtained 
is  necessary  if  the  determination  is  made  at  other  temper- 
atures. Gay-Lussac  has  compiled  a  table  which  indicates 
at  once  the  required  correction ;  the  following  formula  can 
also  be  used :  x  =  c  ±  0.4  /,  where  x  is  the  quantity 
of  alcohol  present  in  the  sample  ;  c  the  degree  indicated 
by  the  alcoholmeter,  and  t  the  number  of  degrees  differing 
from  the  temperature  of  15°  :  the  second  member  of  the 
formula  is  subtracted  from,  or  added  to  the  first,  as  the  tem- 
perature at  which  the  estimation  is  made  is  greater  or  less 
than  15°.* 

In  case  the  wine  to  be  examined  contains  substances  other 
than  water  and  alcohol,  which  would  affect  its  density,  it  is 

*  Tralles    alcoholmeter  is  almost  exclusively  employed  in  this  country. 

— Trans. 


146 


LEGAL    CHEMISTRY. 


necessary,  before  making  use  of  the  alcohol  meter,  to  distil  the 
sample  and  subsequently  examine  the  distillate,  which  will  con- 
sist of  a  simple  mixture  of  water  and  alcohol.  Usually  the 
distillation  is  discontinued  as  soon  as  one-third  of  the  sam- 
ple has  passed  over,  and  a  quantity  of  distilled  water,  suffi- 
cient to  render  the  volume  of  the  mixture  equal  to  the  original 
volume  of  the  wine,  added  to  the  distillate :  the  fluid  re- 
maining in  the  flask  will  be  entirely  free  from  alcohol.  The 
addition  of  water  to  the  distillate  is  not  indispensable,  but 
otherwise  it  is  necessary  to  divide  the  degrees  indicated  by 
the  alcoholmeter  by  3,  in  order  to  reduce  the  result  to  the 
original  volume  of  the  wine  taken. 

M.  Salleron  offers  for 
sale  a  small  apparatus 
(Fig.  1 6)  used  in  exam- 
inations of  this  charac- 
ter, consisting  of  a  flask, 
closed  with  a  gutta-per- 
cha cork,  containing  a 
tube  which  connects  with 
a  worm  passing  through 
a  cooler.  The  flask  is 
supported  by  an  iron 
stand,  and  heated  with  a 
Fig.  go.  gas  or  spirit  lamp. 

In  order  to  estimate  the  cream  of  tartar,  the  wine  is  evap- 
orated to  the  consistency  of  an  extract,  alcohol  of  82°  B.  added, 
and  the  residue  obtained  calcined  in  a  crucible.  The  amount 
of  salt  present  in  the  fused  mass  is  then  determined  by  the 
alkalimetric  method,  as  directed  in  all  works  on  quantitative 
analysis.  The  carbonate  obtained  from  i  gr.  of  cream  of 
tartar  exactly  saturates  9.75  cubic  centimetres  of  a  solution 


WNEGAR.  M7 

containing  i oo  grammes  of  sulphuric  acid  of  66°  B.,  and  iSoo 
grammes  of  distilled  water. 

The  detection  of  toxical  substances,  often  contained  in 
wine,  is  accomplished  by  the  methods  described  under  tb.e 
head  of  detection  of  poisons, 

VINEGAR. 

Vinegar  is  frequently  adulterated  with  water,  and  occa- 
sionally sulphuric  acid  is  added  to  artificially  increase  its 
acidity. 

The  ordinary  reagents — such  as  chloride  of  barium,  or 
nitrate  of  silver — are  not  adapted  to  the  direct  detection  of 
sulphuric  acid,  or  of  other  mineral  acids,  as  sulphates  and 
chlorides,  which  are  as  readily  precipitated  as  the  free  acids, 
may  also  be  present. 

The  following  method,  proposed  by  M.  Payen,  is  usually 
employed : 

Five  centigrammes  of  starch  (fecula)  are  added  to  a  decilitre 
of  table  vinegar,  the  mixture  boiled  for  12  or  15  minutes,  and, 
after  the  fluid  has  become  compktfy  cool:d,  a  few  drops  ef 
iodine  solution  added :  dilute  acetic  acid  does  not  affect 
starch,  and,  in  case  the  vinegar  is  pure,  a  blue  coloration  is 
produced  ;  if,  on  the  other  hand,  even  a  minute  quantity  of  a 
mineral  acid  be  present,  the  starch  is  converted  into  dex- 
trine, and  the  addition  of  iodine  fails  to  cause  a  blue  colora- 
tion. 

The  water  present  is  indirectly  estimated  by  determining 
the  amount  of  acetic  acid  contained  in  the  vinegar.  This  can 
be  accomplished  in  different  ways :  either  the  quantity  of  a 
standard  solution  of  an  alkali,  necessary  to  exactly  neu«- 
tralize  a  measured  quantity  of  the  vinegar,  is  ascertained,  or 


148  LEGAL  CHEMISTRY. 

the  vinegar  is  supersaturated  with  solution  of  baryta,  the  ex- 
cess of  the  salt  eliminated  by  conducting  carbonic  acid 
through  the  fluid,  the  precipitate  removed  by  filtration,  and 
the  baryta  salt  in  the  filtrate  precipitated  by  the  addition  of 
sulphuric  acid.  The  second  precipitate  is  then  collected  on  a 
filter,  washed,  weighed,  and  the  amount  of  acetic  acid  present 
calculated  :  this  is  done  by  multiplying  its  weight  by  0.5 15. 

SULPHATE  OF  QUININE. 

Owing  to  the  high  price  of  this  salt,  it  is  frequently  adul- 
terated. The  substances  used  for  this  purpose  are  :  crystal- 
line sulphate  of  lime,  boric  acid,  mannite,  sugar,  starch,  sali- 
cine,  stearic  acid,  and  the  sulphates  of  cinchonine  and  quini- 
dine.  These  bodies  are  detected  as  follows : 

a.  Upon  slightly  warming  2  grammes  of  sulphate  of  quinine 
with  1 20  grammes  of  alcohol  of  21°  B.,  the  pure  salt  completely 
dissolves ;  if,  however,  starch,  magnesia,  mineral  salts,  or  va- 
rious other  foreign  substances  are  present,  they  are  left  as 
insoluble  residues. 

b.  Those  mineral  substances   that  are  soluble  in  alcohol 
are  detected   by  calcining  the  suspected  sample  :    pure  sul- 
phate of  quinine  is  completely  consumed  ;  whereas,  the  min- 
eral substances  present  remain  behind  as  a  residue. 

c.  In  presence  of  salicine,  the  salt  acquires  a  deep  red  color, 
when  treated  with  concentrated  sulphuric  acid. 

d.  Stearic  acid  remains  undissolved  upon  treating  sulphate 
of  quinine  with  acidulated  water. 

e.  To  detect  sugar  and  mannite,  the  sample  is  dissolved  in 
acidulated  water,  and  an  excess  of  hydrate  of  baryta  added  : 
a  precipitate,  consisting  of  quinine  and  sulphate  of  baryta,  is 


SULPHATE  OIr  QUININE.  149 

produced.  Carbonic  acid  is  then  passed  through  the  fluid,  in 
order  to  precipitate  the  excess  of  baryta  as  insoluble  carbon- 
ate, the  fluid  saturated  with  ammonia,  to  throw  down  the 
quinine  which  may  have  been  redissolved  by  the  carbonic 
acid,  and  the  mixture  filtered.  If  the  salt  be  pure,  no  residue 
will  be  obtained  upon  evaporating  the  filtrate  ;  a  residue  of 
sugar  or  manuite  is  formed,  if  these  substances  are  present. 

f.  Sulphate  of  quinine  invariably  contains  2  or  3  per  cent, 
of  cinchonine,  originating,  not  from   a  fraudulent  admixture, 
but  from  an  incomplete  purification  of  the  salt.     One  of  the 
best  methods  for  detecting  the  respective  quantities  of  quinine 
and  cinchonine,  present  in  a  sample  of  the  sulphate,  is  the  fol- 
lowing :  Several  grammes  of  ammonia  and  ether  (which  has  pre- 
viously been  washed  with  water)  are  added  to  one  or  two  gram- 
mes of  the  salt  under  examination,  the  mixture  thoroughly  agitat- 
ed, and  then  allowed  to  remain  at  rest  The  supernatant  etherial 
solution  contains  all  of  the  quinine  ;  the  cinchouine,  which  is 
almost  completely  insoluble,  both  in  water  and  ether,  remain- 
ing suspended   between  the  layers  of  the  two  fluids.      The 
ether  is  next  removed   by  means  of  a  stop-cock  funnel,  evap- 
orated to  dryness,  and  the  weight  of  the  residue  obtained  de- 
termined.    The   operation  is  then  repeated,  the  ether  being 
replaced  by  chloroform  in  which  both  quinine  and  cinchonine 
are  soluble.     The  residue,  formed  by  the  evaporation  of  the 
second   solution,  will  be  heavier  than  the  first  residue :  the 
difference  between  the  two  weighings  gives  the  weight  of  the 
cinchonine  present. 

g.  The  detection  of  the  presence  of  sulphate  of  quinidine 
is  based  upon  the  difference  in  the  solubilities  of  the  oxalates 
of  quinine  and  quinidine.     Oxalate  of  quinidine  is  sufficiently 
soluble  in  cold  water  not  to  be  precipitated  by  double  de- 
composition when  solutions  of  oxalate  of  ammonia  and  sul- 


150  LEGAL  CHEMISTRY. 

phate  of  quinidine  are  mifced.  Under  the  same  circum- 
stances, quinine  is  almost  completely  thrown  down.  The 
test  is  applied  as  follows  : 

The  suspected  salt  is  dissolved  in  water,  a  slight  excess  of 
oxalate  of  ammonia  added,  and  the  precipitate  formed  sepa- 
rated by  filtration.  If  the  salt  be  pure,  the  nitrate  is  scarcely 
rendered  turbid  by  the  addition  of  ammonia ;  when,  however, 
sulphate  of  quinidine  is  present,  it  will  be  entirely  contained 
in  the  filtrate,  in  which  ammonia  will  produce  an  abundant 
precipitate. 

EXAMINATION  OF  BLOOD  STAINS. 

This  branch  of  legal  chemistry  formerly  gave  but  very  un- 
reliable results.  It  is  scarcely  ten  years  since  the  reactions 
that  are  now  regarded  as  only  secondary  and  confirmative  in 
their  character,  and  far  from  conclusive,  were  the  only  ones  in 
use  :  these  are  the  tests  based  upon  the  presence  of  iron  and 
albumen  in  the  blood.  Since  then,  great  progress  has  been" 
made  in  the  methods  employed.  It  must  not  be  understood, 
however,  that  the  question  under  consideration  always  admits 
of  an  easy  and  decisive  solution  :  the  stains  are  sometimes 
too  greatly  altered  to  be  identified  ;  but  in  cases  where  the  dis- 
tinctive reactions  of  blood  can  be  produced,  the  real  nature  of 
the  stains  under  examination  can,  at  present,  be  determined 
with  certainty. 

The  tests  more  recently  introduced  consist  in  the  produc- 
tion of  small  characteristic  crystals,  termed  haemin  crystals, 
and  in  the  use  of  the  spectroscope.  Crystals  of  haemin  (first 
discovered  by  Teichman)  are  formed  when  dry  blood  is  dis- 
solved in  concentrated  acetic  acid,  and  the  solution  evapora- 
ted to  dryness  :  they  are  of  a  brownish-red  colon  Brticke  first 
suggested  an  analytical  method,  based  upon  this  property  of 


BLOOD  STAINS.  I5I 

blood,  which  is  equally  characteristic  and  sensitive  :  It  is  only 
necessary  to  dissolve  a  minute  portion  of  the  matter  to  be  exam- 
ined (dried  blood,  or  the  residue  left  by  the  evaporation  of  the 
fluid  obtained  by  treating  the  stain,  or  the  dried  blood,  with 
cold  water)  in  glacial  acetic  acid  and  evaporate  the  solution  to 
dryness  in  order  to  obtain  crystals  of  haemin,  which  can  be 
readily  recognized  by  means  of  a  microscope  having  a  magni- 
fying power  of  300  diameters.  If  the  crystals  originate  from 
fresh  blood,  they  appear  as  represented  in 'Fig-  17  ;  crystals 
from  old  blood  are  represented  in  Fig.  18. 


Fig.   21.  Fig.  22. 

The  former  possess  a  reddish-brown,  the  latter  a  lighter 
color. 

The  various  methods  now  employed  to  produce  haemin 
crystals  were  proposed  by  Hoppe-Seyler,  by  Briicke  and  by  Erd- 
man.  Whichever  process  is  used,  the  suspected  stains  are  at 
first  carefully  separated  from  the  material  upon,  which  they  are 
deposited.  If  they  are  present  on  linen,  or  other  fabrics,  the 
stained  portions,  which  always  remain  somewhat  stiff,  are  cut 
off :  they  will  present  a  reddish-brown  color,  in  case  the  cloth 
is  not  dyed  :  if  the  stains  are  on  wood,  they  are  removed  by 
means  of  a  sharp  knife  ;  if  on  stone  or  iron,  they  are  detached 
by  scraping. 

Incase  Hoppe-Seyler's  method  is  used,  the  stains,  separated 
as  directed  above,  are  macerated  with  a  little  cold  water  (warm 
water  would  coagulate  the  albumen  present,  and  consequently 

7 


152 


LEGAL    CHEMISTRY. 


prevent  solution  taking  place)  :  the  stains  become  soft,  striae 
and  brown  or  reddish  clouds  are  observed,  especially  when 
the  dried  blood  is  fresh,  and,  at  the  same  time,  the  objects  upon 
which  the  stains  were  deposited  are  decolorized.  Upon  allow- 
ing the  fluid  obtained  in  this  way  to  spontaneously  evaporate 
on  a  watch-glass,  a  reddish  brown  or  brownish  residue  is  left, 
from  which  the  crystals  of  haemin  are  prepared  in  the  following 
manner :  An  almost  imperceptible  amount  of  common  salt  is 
added  to  the  residue,  then,  six  to  eight  drops  of  concentrated 
acetic  acid,  and  the  mass  thoroughly  mixed  by  stirring  with  a 
small  glass  rod.  The  mixture  is  at  first  heated  over  a  small 
gas  flame,  then  evaporated  to  dryness  by  the  heat  of  a  water- 
bath.  If  the  stains  were  produced  by  blood,  a  microscopic 
examination  of  the  residue  will  reveal  the  presence  of  haemin 
crystals.  This  method  presents  an  objection  :  if  the  stained 
objects  have  been  washed  with  warm  water  previously  to  the 
examination,  the  albumen  will  be  coagulated,  and  the  blood 
rendered  insoluble  ;  in  this  case,  cold  water  will  fail  to  dis- 
solve anything,  and  the  residue  will  not  produce  crystals  when 
treated  with  acetic  acid. 

In  order  to  remedy  this  difficulty  Briicke  operates  directly 
upon  the  stained  woven  or  ligneous  fibre,  or  the  matter  removed 
from  the  stone  or  iron  :  The  materials  are  boiled  in  a  test- 
tube  with  glacial  acetic  acid,  the  fluid  decanted  or  filtered,  a 
trace  of  common  salt  added,  and  the  liquid  then  evaporated 
on  a  watch-glass  at  a  temperature  between  40  and  80°. 
If  the  stains  really  originated  from  blood,  haemin  crystals  will 
now  be  easily  perceptible  upon  examining  the  residue  obtained 
under  the  microscope. 

The  stained  fabric,  the  matter  removed  from  the  stone  or 
iron,  or  the  residue  left  by  the  solution  with  which  the  stains 
have  been  treated,  is  placed  on  the  glass,  a  trace  of  chloride 


BLOOD  STAINS.  153 

of  sodium  added,  and  the  whole  covered  with  a  thin  glass  plate. 
A  drop  of  acetic  acid  is  then  placed  at  the  edge  of  the  plates 
— between  which  it  is  soon  introduced  by  capillary  attraction — 
and  the  mixture  allowed  to  rest  in  the  cold  for  a  few  moments. 
The  mass  is  next  brought  into  solution  by  slightly  heating,  and 
is  then  evaporated  by  holding  the  plate  at  a  considerable  dis- 
tance above  a  gas  burner.  The  fluid  is  examined  from  time 
to  time  under  the  microscope:  when  it  is  sufficiently  con- 
centrated, crystals,  presenting  the  appearance  represented  in 
Figs.  17  or  1 8,  will  be  observed.  These  are  especially  well-de- 
fined, if  an  insoluble  substance  is  also  present  between  the 
plates — which  prevents  their  adhering.  The  fluid  collects  by 
capillary  attraction  at  the  points  of  contact  of  the  plates  as  a 
more  or  less  colored  layer,  in  which  the  crystals  are  deposited. 

Should  the  above  test  fail  to  present  distinctive  indications 
at  first,  one  or  two  fresh  drops  of  acetic  acid  are  introduced 
between  the  plates,  and  the  examination  is  repeated.  The  result 
is  not  to  be  regarded  as  negative,  until  several  trials  have 
proved  fruitless,  as  the  stained  portions  are  but  slowly  soluble, 
and  crystallization  may  have  been  prevented  by  the  too  rapid 
evaporation  of  the  acetic  solution. 

Haemin  crystals,  once  seen,  can  hardly  be  confounded 
with  other  substances  ;  still,  it  is  well  to  identify  them  by  con- 
firming their  insolubility  in  water,  alcohol,  and  cold  acetic  acid, 
as  well  as  their  instantaneous  solubility  in  soda  lye. 

The  addition  of  common  salt  is  ordinarily  superfluous,  as 
it  is  normally  contained  in  the  blood  ;  but  it  is  possible,  if  the 
stains  were  washed  with  Warm  water,  that,  in  addition  to  the 
coagulation  of  the  albumen,  the  solution  of  the  salt  may  have 
taken  place,  in  which  case  crystals  will  fail  to  form.  The 
addition  of  salt  is  to  remedy  this  possible  contingency  ;  albeit, 
the  delicacy  of  the  test  is  not  affected,  even  if  crystals  of  chlo- 


154  LEGAL  CHEMISTRY. 

ride  of  sodium  are  produced,  as  these  are1  easily  soluble  in 
water,  and  are  readily  distinguished  from  those  of  haemin  by 
aid  of  the  microscope. 

The  indications  furnished  by  means  of  the  spectroscope  are 
less  reliable  than  those  given  by  the  production  of  haemin 
crystals  ;  moreover,  the  spectroscopic  examination  requires  fav- 
vorable  weather  fpr  its  execution.  Still,  the  test  should  be 
employed  in  all  possible  instances.  The  course  pursued  is 
the  following : 

The  aqueous  fluid,  with  which  the  stains  have  been  treat- 
ed, is  placed  in  a  watch  glass,  and  evaporated  in  vacua  over 
sulphuric  acid  ;  the  last  remaining  portion  of  the  fluid  being 
united  in  the  bottom  of  the  glass  by  causing  it  to  collect  in  a 
single  drop.  When  the  evaporation  of  fluid  is  completed,  the 
watch-glass  is  placed  before  the  narrowed  slit  of  a  spectro- 
scope, and  a  ray  of  diffused  light  (or  better,  light  reflected  from 
a  heliostat)  made  to  pass  through  the  part  of  the  glass  contain- 
ing the  residue.  If  the  stains  originate  from  blood,  the  ab- 
sorption lines  of  haemoglobin,  consisting  of  two  large  dark 
bands,  to  the  right  of  the  sodium  line  (Frauenhofer*  s  line  D), 
will  be  observed  in  the  spectrum.  In  case  both  of  the  above 
tests  fail  to  give  positive  results,  it  is  almost  certain  that  the 
stains  examined  were  not  caused  by  blood.  If,  on  the  contrary, 
the  reactions  were  produced,  scarcely  any  doubt  exists  as  to  the 
presence  of  blood.  Under  these  circumstances  it  is  advisable  to 
confirm  the  results  by  means  of  the  tests  that  have  been  pre- 
viously spoken  of  as  being  formerly  exclusively  employed ; 
these  are  the  following  : 

a.  y<z  to  i.  c.  c.  of  ozonized  oil  of  turpentine,  i.  e.  turpentine 
which  has  been  exposed  to  the  air  sufficiently  long  to  acquire 
the  property  of  decolorizing  water  that  is  slightly  tinted  with 
indigo — is  introduced  in  a  test-tube,  and  an  equal  volume  of 


BLOOD  STAINS.  !5S 

tincture  of  guaiacum  added  (the  latter  tincture  is  prepared  by 
treating  an  inner  portion  of  the  resin  with  alcohol,  until  its 
brownish  color  is  changed  to  a  brownish-yellow). 

If  upon  adding  some  of  the  substance  under  examination 
to  the  above  mixture  a  clear  blue  coloration  ensues,  and  the 
insoluble  matter  thrown  down  possesses  a  deep  blue  color,  the 
presence  of  coloring  matter  of  the  blood  is  indicated.  The 
mixture  also  imparts  a  blue  color  to  moistened  spots  from 
which  the  blood  stains  have  been  as  completely  extracted  as  pos- 
sible. Unfortunate]/  sulphate  of  iron  gives  the  same  reaction.* 

b.  Upon  heating  the  fluid  obtained  by  treating  the  stains 
with  cold  water  in  a  test-tube,  its  brown  or  reddish  color  disap- 
pears, and  greyish-white    flakes  of   coagulated  albumen   are 
thrown   down.     The   precipitate    acquires    a  brick-red   color, 
when  treated  with  an  acid  solution  of  nitrate  of  mercury  con- 
taining nitrous  acid.     The  albumen  is  also  coagulated  by  the 
addition  of  nitric  acid  :  it  assumes  a  more  or  less  yellow  color, 
if  heated  with  a  slight  excess  of  the  acid.      Chlorine-water, 
especially  upon  heating,  likewise  precipitates  albumen  in  the 
form  of  white  flakes. 

c.  If  the  fluid  is  acidulated  with  a  few  drops  of  acetic  acid, 
and  a  drop  of  ferrocyanide  of  potassium  added,  a  white  pre- 
cipitate, or,  at  least,  turbidity  is  produced. 

d.  The  flakes  of  albumen,  separated  by  heating,  dissolve 
in  caustic  alkalies  to  a  solution,  from  which  they  are  re-precip- 
itated by  nitric  acid,  or  chlorine  water. 

e.  Upon  treating  blood  stains  with  chlorine-water,  a  solution 
which  contains  chloride  of  iron,  and  acquires  a  red  coloration 
by  the  addition  of  sulphocyanide  of  potassium,  is  formed. 

*  Fresh  gluten,  gum  arabic,  and  caseine  also  cause  the  blue  coloration. 

— Trans. 


156  LEGAL    CHEMISTRY. 

f.  Should  the  stains  have  failed  to  be  affected  by  cold  wa- 
ter (which,  as  has  already  been  remarked,  is  the  case  when  they 
have  been  previously  washed  with  hot  water),  they  are  treated 
with  weak  soda  lye.     Nitric  acid,  hydrochloric  acid,  and  chlo- 
rine water  will  produce  in  the  solution  so  obtained  a  white 
precipitate,  which  exhibits  the  general  properties  of  albumen 
previously  described.     In  case  the  stains  are  deposited  upon 
linen,  it   is  necessary   to  replace   the  soda  by  ammonia,   in 
order  to  avoid  dissolving  the  fabric. 

g.  Solutions  of  the  alkalies,  which  dissolve  the  albumen, 
leave   the  coloring  matters  intact,   and  consequently  do  not 
decolorize  the  fabric.     If  the  latter  is  afterwards  subjected  to 
the  action  of  hydrochloric  acid,  the  coloring  matter  is  dissolved, 
forming  a  solution  that  leaves  upon  evaporation  to  dryness 
a  residue  containing  iron,  which  gives  a  blue  coloration  with 
ferrocyanide  of  potassium,  and  a  red  coloration  with  sulphocy- 
anide  of  potassium. 

h.  The  coloring  matter  of  blood  dissolves  in  boiling  alco- 
hol, to  which  sulphuric  acid  has  been  added,  to  a  brown  di- 
chroic  fluid  (appearing  green  by  transmitted  light,  and  red 
by  reflected  light).  A  mixture  of  rust  and  blood  exhibits  the 
same  phenomenon. 

/.  If  substances  containing  blood  are  heated  in  a  dry  tube, 
an  odor  resembling  that  of  burnt  horn  is  emitted.  In  case  the 
stained  fabric  is  a  substance  that  would  produce  this  odor, 
(such  as  wool,  silk,  or  hair),  the  test  naturally  loses  all  value. 

/.  If  the  fluid  obtained  by  treating  the  stains  either  with 
water  or  alkali  is  evaporated  with  a  little  carbonate  of  potassa, 
and  the  residue  heated,  at  first  at  100°,  then  to  redness,  in  a 
glass  tube  to  which  a  fresh  quantity  of  carbonate  of  potassa 
has  been  added,  cyanide  of  potassium  is  formed.  When  cold, 
the  tube  is  cut  above  the  part  containing  the  fused  mixture, 


BLQOD  STAINS. 


157 


the  mass  heated  with  iron-filings  and  water,  the  fluid  filtered, 
and  the  filtrate  then  acidulated  with  hydrochloric  acid  :  fer- 
rocyanide  of  potassium  will  be  present  in  the  fluid,  and 
upon  adding  a  drop  of  solution  of  perchloride  of  iron  a 
green,  or  blue,  color  will  be  produced,  and  a  precipitate  of 
Prussian  blue  gradually  thrown  down. 

If  the  stained  cloth  is  non-nitrogenous  {per  ex. :  hemp, 
linen,  or  cotton),  instead  of  treating  it  with  water,  it  may  be 
heated  until  pulverulent,  mixed  with  carbonate  of  potassa, 
the  mixture  calcined,  and  the  operation  then  completed  as 
just  described.  This  test  having  given  affirmative  results,  the 
operations  should  be  repeated  with  an  unstained  portion 
of  the  cloth,  to  remove  all  doubt  that  the  indications  obtained 
do  not  really  originate  from  the  fabric. 

In  the  present  state  of  science,  it  is  impossible  to  discrim- 
inate chemically  between  human  and  animal  blood.  M.Barruel, 
it  is  true,  is  able,  not  only  to  accomplish  this,  but  also  to  dis- 
tinguish the  blood  of  the  various  species  of  animals  by  its 
odor  !  But  this  test  has  a  somewhat  hypothetical  value  for 
scientific  purposes.  In  regard  to  the  crystals  of  haemin,  they 
do  not  present  sufficient  difference  to  allow  the  blood  of  dif- 
ferent animals  to  be  distinguished.  We  have  not  yet  treated 
of  the  globules.  It  often  occurs  that  these  minute  organs  are 
so  altered  as  to  be  no  longer  recognized  in  the  microscopic  ex- 
amination ;  when,  however,  the  stains  are  tolerably  recent,  they 
may  be  detected  by  examining  the  moistened  stained  cloth, 
directly  under  the  microscope  :  a  discrimination  between  an- 
imal and  human  blood  is  then  possible  :  corpuscules  of  human 
blood  possess  the  greater  size  :  those  of  the  sheep,  for  in. 
stance,  have  only  one-half  the  diameter  of  the  former.  It  is, 
however,  but  seldom  that  this  distinction  can  be  made  use  of.* 

*  Menstrual  blood  is  recognized  by  the  presence  of  epithelial  cells. 

—  Trans. 


I58  LEGAL  CHEMISTRY. 

EXAMINATION  OF  SPERMATIC  STAINS. 

In  cases  where  attempt  at  violence,  rape  or  pederasty 
is  suspected,  the  expert  may  be  required  to  determine  the 
nature  of  stains  found  on  clothing,  sheets,  etc.  The  fact  that 
the  stains  were  produced  by  semen,  may  often  be  regarded, 
per  se,  as  criminating  evidence.  This  class  of  investigation 
possesses,  therefore,  considerable  importance. 

External  appearance  of  the  stains. — Dry  spermatic  stains 
are  thin,  and  exhibit  a  greyish  or,  occasionally,  a  citron-yellow 
color,  if  present  on  white  cloth.  In  case  the  fabric  is  colored, 
they  appear  whitish  and,  if  on  linen,  present  a  glossy  aspect. 
They  are  translucid,  when  observed  by  transmitted  light.  If 
the  fabric,  upon  which  the  stains  are  deposited,  is  of  a  heavy 
texture,  they  are  visible  only  on  one  side :  under  all  circum- 
stances, their  circumference  is  irregular  and  undulated.  These 
indications,  however,  are  not  conclusive,  but  vary  according  to 
whether  the  stains  were  produced  by  the  thick  semen  of  a 
vigorous  man,  or  the  aqueous  seminal  fluid  of  an  aged  and 
diseased  person,  or  by  semen  more  or  less  mixed  with  the 
prostatic  fluid.  Upon  moistening  spermatic  stains,  the  dis- 
tinctive stale  odor  of  fresh  semen  is  sometimes  emitted,  but 
this  characteristic  is  usually  obscured  by  the  presence  of  for- 
eign substances. 

Semen  stains  are  soluble  in  water,  forming  a  gummy  fluid, 
in  which  chlorine,  alcohol,  bichloride  of  mercury,  acetate  and 
subacetate  of  lead  produce  a  white  precipitate,  but  which  fails 
to  be  coagulated  by  heating.  Plumbate  of  potassa  does  not 
impart  a  fawn-color  to  these  stains,  at  a  temperature  above 
20°,  as  is  the  case  with  those  produced  by  albuminous  sub- 
stances. 


SPERMATIC  ST.  1  AYS. 


'59 


Persulphate  of  iron  imparts  to  spermatic  stains  a  pale 
yellow  color, 

Sulphate  of  copper,  a  bluish  grey  color, 

Cupro-potassic  tartrate,  a  bluish  grey  color, 

Nitrate  of  silver,  a  pale  grey  color, 

Nitric  acid,  a  pale  yellow  color. 

The  above  reactions,  separate  or  united,  are  insufficient ; 
they  are  not  very  delicate,  and  are  likewise  produced  by  stains 
originating  from  the  other  varieties  of  mucus  :  the  indications 
furnished  by  a  microscopic  examination  of  the  stains  are  alone 
conclusive 

^ficroscopic  examination. — Semen  contains  as  its  principal 
and  fecundating  constituent,  peculiar  vibratory  filaments, 
(spermatozoa),  held  suspended  in  a  viscous  fluid.  These  fila- 
ments, when  preserved  in  a  warm  and  moist  place,  retain  their 
activity  for  a  considerable  time  :  it  is  even  possible  that  they 
may  exhibit  vitality  in  the  organs,  into  which  they  have  been 
voluntarily  or  forcibly  ejaculated,  for  ten,  or  even  twenty-four 
hours.  "When  exposed  to  cold  air,  the  spermatozoa  quickly 
expire ;  still,  they  preserve  their  form  for  some  time,  and,  as 
this  is  very  characteristic,  it  is  then  easy  to  identify  them  ; 
moreover,  since  they  originate  exclusively  in  the  testicles,  their 
detection  may  be  considered  as  certain  evidence  of  the  pres- 
ence of  semen.  In  stains  produced  by  aged  persons,  and  by 
persons  enfeebled  by  excesses,  the  spermatozoa  fail  to  be 
presented  ;  in  case  they  are  discovered,  this  fact  evidently  does 
not  affect  the  certainty  of  the  spermatic  origin  of  the  stains. 
The  contrary  conclusion  is  never  absolutely  certain  :  still,  if 
the  use  of  the  microscope  fails  to  establish  the  presence  of 
spermatozoa,  it  is  almost  certain  that  the  stains  were  not  pro- 
duced by  semen. 

Of  the  various  methods  for  obtaining  from  the  stains  a 
7* 


160  LEGAL  CHEMISTRY. 

preparation  adapted  to  the  microscopic  examination,  the  one 
proposed  by  M.  Charles  Robin  is  the  most  simple  and  reliable. 

A  strip,  i  c.  c.  in  size  (comprising  the  entire  stain,  if  this 
be  small,  containing  its  inner  portion,  if  it  be  large),  is  cut  from 
the  fabric  under  examination,  care  being  taken  that  the  two 
extremities  of  the  sample  extend  beyond  the  stained  portion. 

One  end  of  the  cloth  is  then  immersed  in  a  capsule,  or 
watch-glass,  containing  pure  water :  the  stains  become  moist- 
ened by  capillary  attraction,  and,  in  a  space  of  time  varying 
from  twenty  minutes  to  two  hours,  acquire  the  appearance  of 
fresh  semen.  As  soon  as  the  stained  portion  becomes  swollen 
and  softened,  the  surface  of  the  cloth  is  gently  scraped  with 
a  spatula,  and  the  substance  removed  placed  on  the  slide  of 
the  microscope.  The  particles  are  next  slightly  detached,  a 
drop  of  water  added,  if  necessary,  and  the  whole  covered 
with  a  small  plate  of  very  thin  glass.  The  preparation  is  then 
examined  by  a  microscope,  having  a  magnifying  power  of  from 
500  to  600  diameters.  In  this  way,  the  presence  of  either 
entire  or  broken  spermatozoa  is  readily  detected-  Their  exist- 
ence is  rendered  still  more  apparent,  if  the  mucus  present 
is  dissolved  by  adding  a  drop  of  acetic  acid  to  the  preparation. 

Entire  spermatozoa  consist  of  long  slender  filaments,  having 
a  length  of  0.04041  to  0.04512  millimetre  ;  the  anterior  extrem- 
ity presents  an  oval  enlargement,  either  round  or  pyriform,  ex- 
hibiting a  double  outline,  when  magnified  to  500  diameters.  This 
enlarged  end  is  termed  the  "  head  ; "  the  entire  remaining 
portion  being  regarded  as  the  "  tail"  In  case  the  spermatozoa 
are  broken,  they  are  severed  either  near  the  head  or  in  the 
middle  of  the  tail,  and  a  mass  of  detached  fragments  will  be 
observed  in  the  microscopic  examination.  The  spermatozoa 
are  not  the  only  corpuscules  revealed  by  the  microscope  ;  other 
substances,  entirely  different  in  character,  are  often  observed. 


SPERMATIC  STAINS.  161 

Although  the  detection  of  these  bodies  is,  in  itself,  of  no  value, 
it  will  be  well  to  enumerate  and  characterize  them  ;  they  are : 

a.  Oily  globules. 

b.  Leucocytes,  or  spherical  and  finely  granulous  globules 
of  mucus. 

c.  Corpuscules,    originating   from    the    seminal   vesicles, 
termed   sympexions.     These  are  rounded   or  ovoid,  possess 
an  irregular  outline,  and  are  usually  mixed  with  the  spermato- 
zoa and  globules  of  mucus. 

d.  Crystals  of  phosphate  of  magnesia,  varying  greatly  in 
size ;  the  largest  are  from  o.mm.  ooi  to  o.mm.  002  in  length. 
The  crystals  formed  upon  cooling  the  semen,  present  the  form 
of  an  oblique  prism,  with  a  rhomboiclal  base.      Occasionally 
they  are  elongated  and  flattened  ;  they  then  assume  the  form 
of  a  rhomboid. 

e.  Epithelial  cells ;  originating  from  the  mucous  follicles  of 
the  urethra. 

f.  Irregular  grains  of  dust ;  soluble  in  acetic  and  hydro- 
chloric acids,  with  gaseous  evolution. 

g.  Brownish-red  grains  of  rust ;  only  slightly  soluble  in 
acetic  acid,  but  easily  soluble  in  hydrochloric  acid. 

//.  Filaments  of  the  strained  fabric;  detected  by  their 
texture,  and  general  appearance. 

/.  Grains  of  starch,  in  case  the  cloth  has  been  stiffened. 
These  are  almost  invariably  swollen,  and  are  frequently  broken 
and  deformed. 

If  the  examination  is  to  be  secretly  executed,  and  the  cloth 
cannot  well  be  cut,  it  is  rolled  in  a  cone,  in  such  a  way  that 
the  external  side  contains  the  stained  portion.  The  lower 
extremity  of  the  cone  (which  should  be  free  from  stains)  is 
dipped  in  a  watch-glass  containing  water,  so  as  to  avoid 
directly  wetting  the  stains.  The  cone  soon  becomes  moistened 


162  LEGAL  CHEMISTRY. 

by  absorption,  and  the  operation  is  then  completed  in  the 
same  manner  as  when  the  fabric  has  been  cut;  which  is 
always  preferable,  when  possible. 

The  examination  of  spermatic  stains  consists,  then,  in 
moistening  the  stains  with  water,  separating  them  as  com- 
pletely as  possible  from  the  stained  cloth,  and  determining 
the  presence  of  the  spermatozoa  by  means  of  the  micro- 
scope. 

All  other  tests  are  valueless;  even  their  execution  for 
confirmatory  purposes  is  not  advisable ;  inasmuch  as  they  fail 
to  possess  a  distinctive  character,  and  the  reagents  employed 
in  their  production  may  destroy  the  fabric,  and  thus  prevent 
the  formation  of  the  only  conclusive  reaction — the  detection 
of  the  spermatozoa. 

In  case  the  stains  are  deposited  upon  a  woman's  chemise, 
they  are  usually  present  on  both  the  front  and  back  portions, 
and  are  sometimes  to  be  found  on  the  sleeves.  When  a  man's 
shirt  is  under  examination,  especial  attention  should  be  given 
to  the  anterior  portions.  The  pantaloons  are  also  often  stain- 
ed ;  usually  in  the  interior,  but  sometimes  also  on  the  ex- 
terior, just  above  the  thighs.  In  reporting  the  decision  to  the 
court,  as  to  the  nature  of  the  stains,  their  precise  position 
should  invariably  be  stated,  as,  by  this  means,  the  circum- 
stances attending  the  commission  of  the  crime  may  be,  at 
least  partially,  elucidated. 

THE   END. 


APPENDIX. 

The  following  list  of  the  literature  of  toxicology,  and  its  allied  branches, 
will,  it  is  hoped,  be  of  service  to  those  readers  who  are  desirous  of  obtain- 
ing further  information  on  the  subjects  treated  in  this  work. — Trans. 

BOOKS. 


Accum ;    A  treatise    on  adulteration    of    food,  and  culinary    poisons. 

London,  1822. 

Adrian  ;  Recherches  sur  le  lait  au  point  de  vue  de  sa  composition,  de  son 
analyse,  de  ses  falsifications  et  surtout  de  l'approvisionnement  de 
Paris.  Paris,  1859. 

Angell  and  Hehner ;     Butter ;  its  analysis  and  adulterations. 

London,  1874. 

Anglada ;    Traite  de  toxicologie. 
Atcherly ;     Adulteration  of  food. 
Bandein ;     Die  Gifte  und  ihre  Gegengifte. 
Beck;     Elements  of  medical  jurisprudence. 
Bellini ;     Lezionis  perementali  di  Tossicologia. 
Bergman ;     Zur  Kentniss  der  putriden  Gifte. 
Bernard ;     Lecons  sur  les  substances  toxiques. 
Billard;     Considerations  medico-legale    sur 

les  irritants. 
Blondlot ;     Sur  la  recherche  de  1'arsenic  par  la  methode  de  Marsh. 

Nancy,  1857. 

Ibid ;      Sur  la  recherche  toxicologique  du  phosphore  par  la  coloration  de 
la  flamme.  Nancy,  1861. 

Ibid ;    Sur  le  dosage  de  1'antimoine  dans  les  recherches  toxicologiques. 

Nancy,  1865. 

Boettcher;     Ueber  Blutkrystalle.  Dorpat.  1862. 

Boiisels;    Ein  Beitrag  zur  Analyse  des  Arsens,  vorzugsweise  in  gericht- 
lichen  Fallen.  Kiel,  1874. 

Borie  ;     Catechisme  toxicologique.  Tuelle,  1841. 

Bouchardt   et   Queveuiie  ;     Du  lait  Paris,  1857. 

Bowman  and  Bloxam ;     Medical  chemistry.  London,  1874. 


Paris,  1835. 
London,  1874. 

Basel,  1869. 
Albany,  1851. 
Firenze,  1865. 
Dorpat,  1868. 

Paris,  1857. 
les  empoisonnements  par 

Paris,  1821. 


1 64  LEGAL  CHEMISTRY.  , 

Briand  et  Chaude ;     Manuel   complet   de   medicine  legale  ;   contcnant 
un  manuel  de  chimie  legale.  Paris,  1873. 

Buchner;    Toxikologie.  Niiremburg,  1859. 

Bureaux;     Histoire  des  falsifications  des   substances   alimentaires. 

Paris,  1855. 

Chapman ;    Manual  of  Toxicology.  London,  1853. 

Chatin;     Recherches     experimentals    et    considerations    sur   quelques 

princips  de  la  toxicologie.  Paris,  1844. 

Chiaje;     Tossicologia.  Napoli,  1835. 

Chaussier;     Medicine  legale.  Paris,  1858. 

Chevalier ;  Dictionaire  des   alterations   et  falsifications   des  substances 

alimentaires,  medicamenteuses  et  commerciales,  avec  1'indica- 

tion  des  moyens  de  les  reconnaitre.  Paris,  1856. 

Ibid ;     Essais  practiques    sur    1'examen    chimique    des  vins,  considere 

sous  la  rapport  judiciaire.  Paris,  1857. 

Christison ;    A  treatise  on  poisons.  Edinburg,  1836. 

Collier;     Paradoxology  of  poisoning.  London,  1856. 

Cooper ;     Tracts  on  medical  jurisprudence.  Phila.  1819. 

Cormenin;      Memoire     sur     1'empoisonnement    par    1'arsenic. 

Paris,  1842. 

Cotter;    Adulteration  of  liquors.  JST.  Y.,  1874. 

Cottereau ;     Des   alterations   et  des  falsifications  du  vin,  et  des  moyens 
physiques  et  chimiques  employe's  pour  les  reconnaitre.  Paris,  1851. 
Cox ;     Poisons  ;  their  effects,  tests  and  antidotes.  London,  1852. 

Culbrush ;     Lectures  on  the  adulteration  of  food,  and  culinary  poisons. 

Newburg,  1823. 

Daltoii;     Adulteration  of  food.  London,  1857. 

Divergie;  Medicine  legale.  Paris,  1852. 

Dragendorff;     Beitrage    zur  gerichtlichen  Chemie   einzelner    organis- 
chen  Gifte.  St.  Petersburg,  1872 

Ibid ;     Untersuchungen  aus   dem  pharmaceutischen     Institut  in  Dorpat 

St.  Petersburg,  1872.. 

Ibid ;  Manuel  de  toxicologie ;  traduit  par  E.  Ritter.  Paris,  1873. 

Druitt;     On  wines.  London,  1866. 

Duflos ;     Die  wichtigsten  Lebenbediirfnisse,  ihre  Aechtheit  und  Giite  ; 

Verunreinigungen,  Verfalschungen,  etc.  Breslau,  1846. 

Ibid ;  Die  Priifung  chemischer  Gifte.  Breslau,  1871 

Ibid ;     Handbuch   der   angewandten  gerichtlich-chemischen  Analyse  der 

chemischen  Gifte  ;  ihre  Erkennung   in  reinem  Zustand  und  in 

Gemischen  betreffend  Leipzig,  1873. 

Duflos    u.    Hirsch ;      Das     Arsen;'  seine    Erscheinung.     u.  s.  w. 

Breslau,  1842. 

Dupasquier;     Consultation    medico-legale    relative   a  une   accusation 

d'empoisonnement  par  le  plomb.  Lyon,  1843. 

Erhard ;     Die  giftigen   pflanzenalkaloiden   und   deren  Ausmitfelung  auf 

mikroskopischem  Wege.  Passau,  1867. 

Eulenberg ;     Die    Lehre    von   den  schadlichen    und    giftigen   Gasen. 

Braunschweig,  1849. 
Flandin  ;    Traite'  des  poisons.  Paris,  1852. 


APPENDIX.  165 

Flandin  et  Danger ;  De  1'arsenic.  Paris,  1853. 

Fop  ;     Adulteration  of  food.  London,  1855. 

Fraise;     Alimentation    publique;    le    lait,    ses    falsifications,    etc. 

Nancy,  1864. 
Frank ;     Manuel  de  toxicologie ;  traduit  de  1'allemand  par  Vrankan. 

Anvers,  1803. 
Fresenius ;    Auffindung    unorganischen  Gifte  in   Speisen,   u.  s.  \v. 

Braunschweig,  1856. 
Friedrich ;    Die   Verfalschung  der   Speisen   und   Getranke. 

Miinster,  1859. 

Galtier;     Traite  de  toxicologie.  Paris,  1855. 

Galtier  de  Claubry ;     De  la  recherche  des  alcalis  organiques  dans  les 

cas  d'empoisonnement.  Paris,  1862. 

Ganeau;     Alterations  et  falsifications  des  farines.  Lille,  1856. 

Garnier ;     Des  falsification  des  substances  alimentaires  et  des  moyens  de 
les  reconnaitre  Paris,  1844. 

Gerhardt ;  Precis  d'analyse  pour  la  recherche  des  alterations  et  falsifica- 
tions des  produits  chimiques  et  pharmaceutiques.       Paris,  1860. 
Garland  ;     Precis  d'analyse  chemique  qualitative.  Paris,  1855. 

Gmelin ;     Allgemeine    Geschichte    der    thierischen  und   mineralischen 
Gifte.  Erfurt,  1806. 

Gorup-Besanez ;       Anleitung     zur    qualitativen     und     quantitativen 
zoochemischen  Analyse.  Braunschweig,  1871. 

Gosse ;     Des  taches,  au  point  de  vue  medico-legale.  Paris,  1862. 

Griffin ;  The  chemical  testing  of  wines  and  spirits.  London,  1872. 

Griffith   and  Taylor;     A  practical  manual  of   the    general,  chemical, 
and  microscopical  character  of  the  blood,  etc..  London,  1843 
Gnerin  ;  Nouvelle  toxicologie.  Paris,  1826 

Guy ;  Principles  of  forensic  medicine.  London,  1843 

Gwosdeu;     Ueber   die    Darstellung  des  Hamin  aus  dem  Blut  und  den 
qualitativen  Nachweis  minimaler  Blutmengen.         Wien,  1866. 
Hager;     Untersuchungen.  Leipzig,  1873. 

Hartung-Schwarzkoff ;    Chemie    der    organischen     Alkalien. 

Miinchen,  1855. 

Hassall;     Adulteration  of  food.  London,  1855. 

Van  Hassett;     Handbuch  der  Giftlehre.  Braunschweig,  1862. 

Helwig;     Das  mikroskop  in  der  Toxikologie.  Mainz,  1864. 

Herman;     Lehrbuch  der  experimentellen  Toxikologie.  Berlin,  1875. 

Hitzig;     Studien  iiber  Bleivergiftung.  Berlin,  1870. 

Hoffman;     Manual  of  chemical  analysis.  N.  Y.,  1873. 

Hoppe-Seyler ;      Handbuch     der     physiologisch     und     pathologisch 
chemischen  Analyse.  Berlin,  1870. 

Ibid ;     Medicinisch-chemische  Untersuchungen.  Berlin,  1871. 

Horsley  ;     The  toxicologist's  Guide.  London,  1866. 

How ;     Adulteration  of  food  and  drink.  London,  1855. 

Huseman;     Handbuch  der  Toxikologie.  Berlin,  1870. 

Jaillard ;    De  la  toxicologie   du  bichromate   de  potasse. 

Strasbourg,  1861. 
Jones    (H.  Bence);    Chemistry  of  wines  London,  1874. 


166  LEGAL  CHEMISTRY. 

Klincke;       Die  Verfalschung  der   Nahrungsmittel,    Getranke,  etc 

Leipzig,  18:58. 

v.  Kupffer;     Handbuch  der  Alkoholometrie.  Wien,  1866. 

de   Lapparent;     Les  moyens  de   constater   la  purete*  des  principales 
huiles  fixes.  Cherbourg,  1855. 

Lef ort ;     Etudes  chimiques  et  toxicologiques  sur  la  morphine. 

Paris,  1861. 
Legrand  ;     Traite  de  medicine  16gale  et  de  jurisprudence  mddical. 

Paris,  1873. 

Letheby ;    On  food.  N.  Y.,  1872. 

Lerwin  ;    Toxikologischen  Tabellen.  Berlin,  1856. 

Liebreich;     Outlines  of  Toxicology.  London,  1875. 

Lindes;     Beitrage  zur  gerichtlichen  Chemie.  Berlin,  1852. 

Lunel;     Guide  pratique  pour  reconnaitre  les  falsifications  et  alterations 
des  substances  alimentaires.  Paris,  1874. 

Malle ;     Essai  d'analyse  toxique  gcnerale,  Strasbourg,  1838. 

Marset;     Composition,  adulteration,  and  analysis   of  food. 

London,  1856. 

Marshall;     Remarks  on  arsenic.  London,  1817. 

Marx;     Geschichtlich  Darstellung  der  Giftlehre.  Gottingen,  1829. 

Mata ;     Tratado  de  medicina  y  cirugia  legal.  Paris,  1874. 

Mayercon  and  Bergeret ;     Recherches  sur  la  passage  de  1'arsenic  et 
de  1'antimoine  dans  les  tissus  et  les  humeurs.     Paris,  1874, 
Meissner ;    Araometrie  in  ihrer  Anwendung  auf  Chemie  und  Technik. 

Wien,  1816. 

Mitchell;     Falsification  of  food  London,  1848 

Mohr ;     Chemische  Toxikologie.  Braunschweig,  1874 

Moiiier ;     Memoires  sur  1'analyse  de  la  lait  et  des  farines, 

Paris,  1858. 

Montgarney;     Essai  de  toxicologie.  Paris,  1818. 

Muller ;     Anleitung  zur  Priifung  der  Kuhmilch.  Bern,  1858. 

Muiik  und  Leyden;     Phosphorvergiftung.  Berlin,  1865. 

Neubauer;     Chemie  des  Weines.  Wiesbaden,  1874. 

Neumaii ;     Die     Erkennung    des   Bluts    bei  gerichtlichen    Untersuch- 
ungen.  Leipzig,  1869. 

Normandy  ;    The  commercial  hand-book  of  chemical  analysis. 

London,  1875. 

Odling  ;     A  course  of  practical  chemistry.  London,  1872. 

Oesterlen ;    Das  menschliche  Haar  und  seine  gerichtartliche  Bedeutung. 

Tubingen,  1875. 

Orfila ;  Rapport  sur  les  moyens  de  constater  la  presence  de  1'arsenic  clans 

les  empoisonnements  par  ce  toxique.  Paris,  1841. 

Ibid;     Traite  de  medicine  legale.  Paris,  1848. 

Ibid ;     Elements  de  chimie  medicale.  Paris,  1851. 

Ibid ;     Traite  de  toxicologie.  .  Paris,  1852. 

Otto ;     Anleitung  zur   Ausmittelung  der  Gifte,   und  zur   Erkennung  der 

Blutflecken  bei  geriditlich-chemischen  Untersuchungen. 

Braunschweig,  1870. 
Payen ;    Substances  alimentaires.  Paris,  1856. 


APPENDIX.  167 

Pelliken;      Beitrage     zur     gerichtlichen     Medizin,   Toxikologie     und 

Pharmakodynamik.  Wiirztburg,  1858. 

Petit  Lafitte ;     Instruction    simplified    pour    la    constatation  des    pro 

prie'tees  des  alterations  et  des  falsifications  des  principales. 

denre'es  alimentaires.  Bordeaux,  1858. 

Plaff ;     Anleitung  zur  vornahme  gericthlicher  Blutuntersuchungen. 

Plauen,  1860. 

Pierce  ;     Examination  of  drugs,  chemicals,  etc.  Cambridge,  1852. 

Flanta;     Verhaltung  der  wichtigsten  Alkaloiden  gegen  Reagenten. 

Heidelberg,  1846. 

Pleck;     Toxicologia.  Viennae,  iSor. 

Prescott;     Chemical  examination  of  alcoholic  liquors.  N.  Y.,  1875. 

Preyer;    Die  Blutkrystalle.  Jena,  1871. 

Reese ;     A  manuel  of  Toxicology.  Phila.,  1874. 

Reveil;     Introduction  &  un  cours  de  toxicologie.  Paris,  1859. 

Reyer  ;     Die  Blausaure  physiologisch  untersucht.  Bonn.,  1868. 

Rich  ;     The  analyst's  annual  note-book  for  1874.  London,  1875. 

Ritter ;     Ueber   die    Ermittelung   von  Blut,   Satnen  und  Excrementen- 
flecken  in  Kriminalfallen.  Wiirztburg,  1854. 

Ibid ;     Bcitriige  zur  gerichtlichen  Chemie.  St.  Petersburg,  1872. 

Ibid ;      Manuel     de     chimie     practique,    analytique,     toxicologique     et 
zoochimique.  Paris,  1874. 

Robinet    (fils) ;      Manuel     practique  d'analyse   chimique   des   vins. 

Paris,  1872. 

Rebuteau;    Elements  de  Toxicologie  et  de  medecine  legaleappliquee  a 
rempoisonnements.  Paris.  1873. 

Roucher ;     Recherches  toxicologiques.  Paris,  1852. 

Roussin  ;     Falsification  des  vins  par  1'alun.  Paris,  1861. 

Ryan  ;     Medical  Jurisprudence.  London,  1836. 

Schmidt ;    Ein  Beitrag  zur  Kentniss  der  milch.  Dorpat  1874. 

Schmidt;     Diagnostik  verdachtlicher  Flecken.  Leipzig,  1848. 

Schneider ;     Die  gerichtliche  Chemie.  "\Yicn,  1852. 

Schroff ;     Toxikologische  Versuche  iiber  Arsen.  \Vien,  1858, 

Ibid ;     Beitrage  zur  Kentniss  des  Aconite. 

Simon;  Die  Frauenmilch.  Berlin,  1838. 

Sonuenkalb ;  L'Aniline  et  ses  couleurs,  au  point  de  vue  toxicologique. 

Leipzig,  1864. 
Sonnenschein ;     Ueber  ein  neues  Reagent  auf  Alkaloiden. 

Berlin,  1857. 

Ibid ,'     Handbuch  der  gerichtliche  Chemie.  Berlin,  1869. 

Soubeiran ;     Nouveau  Dictionnaire  des  falsifications  et  des  alterations 
des  aliments,  etc.  Paris,  1874. 

Speyer ;    Recherche  de  la  colchicine.  Dorpat,  1870. 

Spratt;     Toxicology.  London,  } 843. 

Stowe  ;     A  toxicological  chart.  London,  1872. 

Tanner;     Memoranda  on  Poisons.  London,  1872. 

Tardieu ;     Etude  medicol^gale  sur  1'empoisonnement.  Paris,  1866. 

Tardieu,  Lorain  et  Roussin;    Empoisonnement   par   la  strychnine, 
1'arsenic,  et  les  sels  de  cuivre.         Paris,  1865. 


i68  LEGAL  CHEMISTRY. 

Tatra;     Traite  d'empoisonnement  par  1'acide  nitrique.  Paris,  1802. 

Taylor ;     Poisoning  by  strychnine.  London,  1856. 

Ibid ;     On  poisons,  in  relation  to  medical  jurisprudence  and  medicine. 

London,  1859. 

Ibid ;     A  manual  of  medical  jurisprudence  Phila.,  1873. 

Ibid  ;    The  principles  and  practice  of  medical  jurisprudence. 

Phila.  1873. 

Thompson;     Medical  jurisprudence.  London,  1831. 

Traill ;     Medical  jurisprudence.  Phila.,  1841. 

Trommer;     Die  Kuhmilch   in    Berzug   auf   ihre  Verdiinnung  und  Ver- 

falschung.  Berlin,  1859. 

Valaer;      Etude   sur  la  recherche,    les    caracteres    distinctifs,    et  la 

dosage  des  alcaloides  organiques  naturels.  Paris,  1862. 

Vernois ;    Du  lait   chez   la   femme  dans  1'etat  de  sante'  et  dans  1'etat  de 

maladie.  Paris,  1858. 

Vogel;     Eine  neue  Milchprobe.  Stuttgart,  1860. 

Walchner ;       Die  Nahrungsmittel    des  menchens,  ihre  Verfalschungen 

und  Verunreinigungen.  Berlin,  1875. 

Walther ;    Ueber  Erkennung  des  Arsens  bei  Arsenvergiftung. 

Bayreuth,  1854. 

Wanklyn ;    Milk  Analysis.  London,  1874. 

Wenke ;     Das  Bier  und  seine  Verfalschung  Weimar,  1861. 

Werber ;  Lehrbuch  def  praktischen  Toxikologie.  Erlangen,  1870. 

Wharton  and  Stille;     Medical  Jurisprudence.  Phila.,  1855. 

Wickler;     Toxikologische  Briefe.  Weimar,  1852. 

Wirthgen;     Die  verschiedenen   Methoden   zur  ermitteluns;    von    Blut- 
flecken  in  forensischen  Fallen.  Erlangen,  1861. 

Witting ;    Uebersicht  der  wichtigsten  Erfahrungen  in  der  Toxikologie. 

Hannover,  1827. 

Wohler  und  Liebold;      Das   forensisch-gerichtlichen   Verfahren  bei 
einer  Arsenvergiftung.  Berlin,  1847. 

Wood;     Therapeutics,  materia  medica  and  Toxicology.        Phila.,  1874. 
Wormely;     The  micro-chemistry  of  Poisons.  N.  Y.,  1867. 

Wurtz;       Chimie  medical e.  Paris,  1868. 

Zalewsky;   Untersuchung  iiber  das  Conio,  Dorpat,  1869. 


MEMOIRS. 

On  poison*  generally  and  those  not  elsewhere  classified. 

Accum ;     Ed.  month.  Rev.  iii,  276 ;  Quar.  Rev.  xxiv,  341 ;  Ed.  Rev. 

xviii,  370 

Andrews ;     Sill  Am.  Jour.  [2]  xlvii,  25. 
Bouis;     Compt.  rend.  Ixxiii. 
Bunsen ;     Ann.  Ch.  Pharm.  cvi,  i. 
B runner ;     Archiv.  der  Pharm.  ccii,  4. 


APPENDIX.  169 

Cossa;     Gaz.  Med.  di  Lomb.,  1863. 

Diakanow;  Med.  Chem.  Unters  ii,  144. 

Duflos  u.  Milloii ;     Ann.  Chem.  Pharm.  xlix,  308. 

Elliot  and   Storer ;     Am.  Jour.  Pharm.,  Sept.,  1860 

Joubert ;     Compt.  Rend.,  No.  26. 

Moicessier;     Annal  d'Hygiene,  1868. 

Orfila ;     Mem.  de  Pacad.  roy.  de  mod.  viii.  493. 

Otto ;     Ann.  chem.  Pharm.  c.,  39. 

Pellissie ;     Jour,  de  Pharm.  et  de  chim.,  Jan.,  1874. 

Reveil;     Compt.  Rend.  lx,  433. 

Reynolds;     The  Irish  Hosp.  Gaz.  Feb.  15,  1873. 

Selmi ;     Gaz.  Chim.  Ital.  1874.  fasc.  I,  ii. 

Stein  ;     Polyt.  Centralb.  1866,  p.  1023  and  1870,  pp.  1035,  1209. 

Viercnow ;     Arch.  £.  path.  anat.  xxi,  444. 

Ou  the   destruction  of  organic    matter. 

Brande ;     Arch.  f.  Pharm.  xlviii,  206. 
Buchner ;     N.  rept.  f.  Pharm.  xvii,  21. 
Fresenius ;     Zeitsch.  f.  anal.  Chem.  i  Jahrg,  447. 
Fype ;    Jour.  f.  prakt.  Chem.  Iv,  103. 
Graham;     Phil.  Mag.  [4]  xxiii. 
Liebig;     Chem.  Centbl.  1857^.357. 
Ludwig;     Arch.  f.  Pharm.  xcvii,  p.  23. 
Schacht;     Arch.  f.  Pharm.  Ixxvi,  139. 
Schneider;     Jahrb.  der  Chem.  1851,  630. 
Sonnenschein  ;     Deutsche  Klinik,  1867,  No.  3. 
Wurtz ;     Am.  Jour.  Sci.  [2]  xi,  405. 

On  the  detection  of  Arsenic. 

Avery ;    Sill  Am.  J.  [2]  xlvii,  25. 

Barker ;     Am.  Chem.  June,  1872. 

Becker ;     Arch.  f.  Pharm.  xlvi,  287. 

Bettendorff ;     Zeitsch.  f,  Chem.  v.  492:  592. 

Blondlot;     Jahresb.  1863,  681 ;  Compt.  Rend.  July  7,  1845. 

Bloxam  ;      Jahresb.  f.  Chem.   1860.    645 ;  Chem.   Soc.  Q.  Jour,  xiii,  14, 

138. 

Brescius;     Ding.  poly.  Jour,  clxxxvi,  226. 
Buchner ;     Rept.  f .  Pharm.  xii. 
Christison ;     Lond.    and    Eclinb,  Jour.    Med.    Sc.,  Sept.,  1843 ;  Med. 

Recorder,  Apr.,  1827. 
Davy;     Jahresb.,  1858,  609 
Draper;     Dins;!,  poly.  Jour.  cciv.  385, 
Elliot  and  Storer  ;     Sill.  Jour.  32,  p.  380. 
Erlenmeyer ;     Zeitsch.  f.  Ch.  u  Pharm.  1862,  38. 
Feuchtwanger ;    Sill.  Jour,  xix,  339. 
Franck;     Zeit.  f.  anal.  Chem.  iv.  201. 


170  LEGAL  CHEMISTRY, 

Fresenius ;     Arch.  f.  Pharm.  Ixii,  57  ;    Ann.   der.  Chem,  u.  Pharm.  xliii. 

361 ;  ibid,  xlix,  275;     Zeits  f.  anal  Chem.  vi,  196;  ibid  ii,  19; 

ibidi.  483;  Qual,  Chem.  Anal.  p.  346. 
Fresenius   u.    v.    Baho ;      Pogg,    Anal.    vol.   xc,    ^65 ;    Ann.  Chem. 

»  Pharm.  xlix,  287. 

Fype;     Phil.  mag.  ii  487  ;  Jour  f.  prakt.  Chem.  Ix.  103. 
Gatehouse ;     Chem.  News.  No.  699,  1873. 
Gaultier  de  Claubry ;    J.  Pharm.  [3]  xxii,  125. 
Graham;     Ann.  Chem.  Pharm.   cxxi,  63:  Elements  of  Chem.   2nd.  edit. 

vol.  ii,  215. 

Gray ;     Chem.  News,  v,  23  p.  73. 
Hager;     Pharm.  Zeitsch.  1870,  No.  27:  Ding.  poly.  Jour.  vol.  207,  No.  6; 

Centralhalle  xiii,  195. 
Hasson;     Compt.  Rend.  Ixvii,  56. 
Houzeau ;     Ding.  poly.  Jour.  Bd.  207,  Heft.  2,  3. 
Hume;     Phil.  Mag.  Sept.  1812,  109. 
Keber;     Viertlj.  f.  gerichtl.  Med.  ix.  96. 

Kirschgassner ;     J.  f.  prakt.  Chem.  Ixviii.  168;  Jahresb.  1860,  170. 
Lippirt ;     J.  f.  prakt.  Chem.  Ixviii,  168  ;  Jahresb.,  1860, 170. 
Lois;     Oest,  Zeitsch.  f.  prakt.  Heilkunde,  xlix,  1859. 
Mayer;     Pharm.  Zeitsch.  Russ.  2  Jahrgang. 
Meyer;     Ann.  Chem.  u.  Pharm.  Ixvi. 
Montmeja;     La  France  Med.,  Jan.  8,  1873. 

Odling;   Guys.  Hosp.  Rep.  [3]  v.  367;  Zeitsch.  f.  anal.  Chem.  ii.  388. 
Pearson;     Sill,  Am.  J.  [2]  xlviii,  190. 
Puller ;     Zeitsch.  f.  anal.  Chem.  x,  52. 
Rose;     Pogg.  Annal.  vol.  xc;  Zeitsch.  f.  anal.    Chem.   i, 418;    Chimie 

Anal.  Paris,  1859,  p.  405. 
Roussin;    Jahresb.  1866,  801. 
Saikowski;     Arch.  f. path.  Anat.  xxxi,  400. 
Selmi;     Dent.  Chem.  Gess.  Ber.  1872,  477. 
S chafer;     Jour.  f.  prakt.  Chem.  Ixxxii,  286. 
Schneider;     Wien.  Akad.  Ber.  1851,  vi,  409 
Sklarek;     Arch.  f.  Anat.  u.  Phys.  1866,  481. 
Slater;    Chem.  Gaz.  1851,  57. 

Sonnenschein ;     Arch.  f.  Pharm.  cxciii,  245  :  ibid.  [2]  cxliii.  250. 
Taylor ;    Guys.  Hosp.  Rep.  ii,  83 ;  ibid,  vi ;  Pharm.  Zeitsch.  f.  Russl.  10, 

Jahrg.  129. 

Ugers;     Ann.  Chem.  Pharm.  clix,  127. 
"Ores ;     Diet.  Arts,  etc.,  new  edit,  i,  189. 
Vitry ;     Annal  d'hygiene  publ.  xxxvi,  14. 
Wackenroder  ;     Arch.  f.  Pharm.  Ixx,  14. 
Watt's  Chem.  Diet,  i,  365;  Supp.  215. 
Werther;     J.  pr.  Chem.  Ixxxii,  235;  Jahresb.  1861,  851. 
Wiggers ;     Canstatt's  Jahresb.  der  Pharm.  1864. 
Wittstein ;     Zeitsch.  f.  anal.  Chem.  ii,  19. 
Wohler;     Ann.    der   Chem.   u.   Pharm.    Ixix,   364;    Mineral    Analyse, 

Gottingen,  1861,  213. 
Wood  and  Doremus;    N.  Y.  Med.  Press,  1859,  543. 


APPENDIX.  171 

Zenger  ;     Zeitsch.  f.  Ch.  Pharm.  1862,  38  ;  Jahresb.  1862,  595. 
On    the   detection  of    Antimony. 

Bellini ;    Jhb.  f.  Pharm.  1868,  p.  453. 

Bottger;     Chem.  Centralbl,  3jahrgang, 

Buusen ;     Ann.  Chem.  Pharm.  cvi,  p.  3. 

Hofman;     Ann.  Chem.  Pharm.  p,  155;  Chem.  Soc.  Quar.  J.  xiii,  79. 

Millon  and  Levaran;     Compt.  Rend.  21. 

Odling ;     Guys  Hosp.  Rep.  [3]  ii,  249. 

Pfaff ;     Pogg.  Ann.  f.  Phys  xl,  339. 

Thompson ;    Jour.  f.  prakt.  Chem.  ii,  369. 

Vogel ;    ibid,  xiii,  57. 

On   the   detection   of   Mercury. 

Buchner ;     N.  rept.  f.  Pharm.  xvii,  272. 

Erdman  and  Marchaud ;    Jour  f.  prakt.  Chem.  xxxi. 

Hittdorf ;     Pogg.  Annal.  cvi. 

Konig  ;    Jour.  f.  prakt.  Chem.  Ixx. 

Mayencon  and  Bergeret;      Jour,  de  1'Anat.  et  de   la   Physiol  1873, 

No.  i  ;  Jour,  de  Pharm.  et  de  Chim.,  Aug.,  1873. 
Schneider;     Ber.  d.  Wien,  Akad.  d.  Wiss.  xl. 
Wormley ;    Chem.  News,  ii,  No.  43. 

On   the   detection  of  Phosphorus. 

Barrett;     Phil.  Mag.  [4]  xxx,  321. 

Blondlot;    Jour.  de.  Phy.  et  de  Chim.  3  6  serie  xl,  p.  25. 

Bostelaer ;    Jour,  de  Pharm.  et  de  Chim.,  May,  1873. 

Christoffle  and  Beilstein ;     Ann.  de  Chim.  v,  iii,  p.  80. 

Dalmon;    Zeitsch.  f.  anal.  Chem.  1871,  132. 

Dusard;     Zeitsch.  f.  anal.  Chem.  i,  129;    Compt.  rend,  xliii,  1126. 

Ferrand ;     La  France  med.,  Jan.  18,  1873. 

Fresenius  and  Neubauer ;     Zeitsch.  f.  Anal.  Chem.  i,  366. 

Hager;     Zeitsch  f.  anal.  Chem.  1870,  465. 

Hoffman;    Jahresb.  1859,663. 

Klewer ;     Pharm.  Zeitsch.  f .  Russl.,  386. 

Kohler;     Poly,  centralh,  1871,  263. 

Lapeyrere ;     La  France  mcd.,  Jan.  4,  1873. 

Lefort;    Jour  de  Pharm.  et  de  Chim.,  Aug.,  1874. 

Lispowitz;     Ann.  f.  Phys.  u.  Pharm.  cviii,  625. 

Mistcherlich ;    Jour.  f.  prakt.  Chem.  Ixvi,  238. 

Mulder  ;     Arch.  f.  d.  holl.  Zeit.  ii,  4  ;   Zeitsch.  f.  Anal.  Chem.  ii,  3. 

Otto ;     Zeitsch,  f.  Chem.  [2]  ii,  733. 

Fribram  ;     Zeitsch.  f.  anal.  Chem.  1871,  109. 

Ritter ;     These  de  doctorat  es  sciences  :  Paris,  1872. 

Scherer ;     Ann.  Ch.  Pharm.  cxii,  214. 


172  LEGAL  CHEMISTRY. 

Schieffendecker  ;     Zeitsch.  f.  anal.  Chem.  1872,  iii. 
Schom ;    Zeitsch.  f.  anal.  Chem.  [2]  v,  664. 
Wiggers ;    Canstatt's  Jahresb.  f.  Pharm.  1854. 

On   the  detection  of  JPrussic    Acid. 

Almen;     Chem.  Centralb.  1871,  797. 

Bonjeau;     Compt'  rend.  Ixx,  532. 

Brauu ;     Zeitsch.  f.  anal.  Chem.  iii,  464. 

Duvignan  and  Parent ;     Am.  Med.  Rec.  1819,  534. 

Hagenbach;     Arch.  f.  path.  Anat.  xl,  125. 

Hoppe-Seyler ;     Vierschow's  Arch.  f.  path.  Anat.  38. 

Jacquemin;     Compt.  rend.lxxxix,  1499,  1502. 

Letheby ;     Lond.  Lane.  1844,  244;  ibid,  vol.  2,  p.  139. 

Ralph;     N.  Jahresb.  f.  Pharm.  xxx,  179. 

Rennard;     Pharm.  Zeitsch.  f.  Russl.  xii,  No.  8. 

Schonbein ;    Zeitsch.  f.  anal  Chem.  i868,.5O3. 

Siegel ;    -Arch.  f.  Heilkunde,  1858. 

Struve ;  Zeitsch.  f.  anal.  Chem.  1873,  i;  Mon.  Scien.  Ques.  Juin,  1874,  538. 

Taylor ;  Ann.  Ch.  Pharm.  Ixv,  263. 

On  the  detection  of  Alkaloids  in  general. 

Anderson;  Pharm.  Centralbl,  1848,  591. 

Armstrong ;  J.  Chem.  Soc..  v,  8,  p.  56. 

Back ;  Jour.  f.  prakt.  Chem.  Nos.  5-6,  1873. 

Beas;  Jour  de  Phys.  et  de  Chim.,  Sept.  1872. 

Bolton;  (trans,  of  the  Stas-Otto  method)  Am.  Chem.,  Nov.,  1873. 

Bonnemains;  Compt.  Rend,  xxxvi,  150. 

Bouchardt ;  Ann.  de  Phys.  et  de  Chim.,  36  serie.  t.  ix. 

Brunner ;     Archiv  der  Pharm.,  April,  1873. 

Buignet ;    Jour,  de  Pharm.  et  de  Chim.  t.  xx,  252. 

Deane  and  Brady  ;     Chem.  Soc.  J.  [2]  iii,  34. 

Deefs;  N.  Jahresb.  f.  Pharm.  ii,  31 ;  Wittstein's  Viertelj.  vi. 

Dragendorff ;   Pharm.    Zeitsch,   f.    Russl.  ii,   459;  Archiv  der  Pharm. 

May,  1874 

Erhard;     N.  Jahresb.  f.  Pharm.  xxv,  129,  193,  283;  ibid,  xxvi,  9,  129. 
Ewers ;     Pharm.  Zeitsch.  f.  Russl.  xii,  No.  23. 
Graham  and  Hofman ;    Chem.  Soc.  Qu.  J.  v,  173 ;  Pharm. J.  Trans,  xi, 

504 ;  Ann.  Ch.  Pharm.  Ixxxiii,  39. 
Grandean;    Bull.  Soc.  Chim.  [2]  ii,  74 
Guy;     Pharm.  Jour,  ii,  pp.  553,  602;  ibid,  iii,  pp.  ii,  112. 
Hagers ;     Chem.  Ctbl.,  1869,  131. 
Horsley ;     Chem.  News,  v,  355 
Huseman;     Ann.  Chem.  Pharm.  cxxviii.  305. 
Kletzinsky ;     Mitthel.  v.  d.  Geb.  d.  rein  u.  angew.  Chem.  1865. 
Kohler ;     Archiv  der  Pharm.  Mar.  1873. 


APPENDIX.  173 

Kuhne  ;    Ann.  Chem.  Pharm.  vol.  civ. 

Lef ort ;    Zeitsch.  f.  anal.  Chem.  i,  134. 

Lehrman;     Archiv  der  Pharm.  2  Bd.  Ixxvi,  144. 

Iiiebig,  Poggendorff  u.   Wohler  ;   Handworterb.  d.  Chem.   2  Aus.  i, 

464. 

Macadams;     Pharm.  Jour.  Trans,  xvi,  120,  160. 
Marchattie;     Chem.  News,  x,  183. 

Marine;     Bull.  Soc.  Chim  [2]  ix,  203;  Zeitsch.  f.  rat.  Med.  1867. 
Mayer;    Jour  de    Pharm.   et    de  Chim.,    Oct..   1873;  Oest  Zeitsch.  f. 

Pharm.  ii,  232. 
Nowak ;    Dingls.    poly.   Jour.,  vol.     206,   p.   422 ;  Sitzber.  d.   Wiener 

Akad.  d.    Wissensch.,  1872 
Otto ;    Ann.  Ch.  Pharm.  c,  39. 
Orfila;    Jour.  de.  Chim.  et  Med.  [4]  t.  vii,  397. 
Palm  ;    Pharm.  Zeitsch.  f.  Russl.  i,  Jahxgang. 
Pierce ;    J.  Chem.  Soc.,  Nov.  1874. 
Prollius;     Chem.  Centralbl,  1857,231. 
Ritter ;     Pharm.  Zeitsch.  f.  Russl   5-6  Jahrg. 
Rodgers     and    Girdwood ;  Jahresb.  v.  Liebig    u.    Kopp,  1857,  603 ; 

Pharm.  Jour.  Trans,  xvi,  497. 

Rorsch  and  Fasbender  ;     Deut.  Chem.  Gess.  Ber.  xii,  1064. 
Scheibler;    Jahresb.     1863,   702;    Arch.   f.    Pharm.  lix ;  Jour.  £.  prakt. 

Chem.  Ixxx,  211. 

Schneider;    Ann.  Chem.  Pharm.,  von  vPoggendorff,  No.  9. 
Schrage  ;     Archiv  der  Pharm.,  Dec.,  1874. 
Schroof ;     Apothet.  Jahrg.,  ix,  148. 
Schulze ;     Ann.  Ch.  Pharm.  cxix,  177, 
Schwanert ;     Deut.  Chem.  Gess.  Ber.,  No.  14,  1874. 
Sonnenschein ;    ibid,  civ,  45. 
Stas;     Bull,    de    1'Acad.   Roy.de  Med.   de   Belgique,   xi,   304   (1851); 

Ann.  Ch.    Pharm.,   Ixxxiv,   379,  J.  Pharm.   Chim.,  xxii,  281 ; 

Jahresb.,  1851  640 ;  Jour.  f.  prakt.  Chem.,  lix,  232. 
Struve;    Zeitsch.  f.  anal.  Chem.,  No.  2,  1873. 
Thomas;    ibid,  vol.  {,317. 
v.  Uslar   and    Erdman ;    Ann.   der     Chem.  u.  Pharm.,  120,   p.  121  ; 

122,  p.  360. 

de  Vrij  and  van  der  Burg;  Jahresb.  v.  Liebig  u.  Kopp,  1857,  602. 
"Watts;     Chem.  Diet.,  vol.  i,  p.  125. 
"Wagner ;     Fresen.  Zeitsch.  f.  anal.  Chem.,  iv. 


On  Airopine. 


Brunner ;     Archiv  der  Pharm.,  April,  1873. 
Calmberg ;     ibid.  Nov.,  1874. 
Gulielmo  ;     Zeitsch.  £.  anal.  Chem.,  ii,  404. 
Helwig;     Wiener  Akad.  Ber.  vii,  433. 
Koppe ;     Pharm.  Zeitsch.  f.  Russl.,  5  Jahrgang, 


I74  LEGAL  CHEMISTRY. 

Pelikan :    ibid,  i  Jahrgang: 

Wormley;    Chem.  News,  vol.  ii,  June,  1860. 

On  Itniciuc. 

Cotton ;    Zeitsch.  f.  Chem.  [2]  v.  728. 
Helwig ;    Zeitsch.  £.  anal.  Chem.,  iii,  43. 
Luck ;    Zeitsch.  f.  Chem.  [2]  vi,  275. 
Mayer :     Rep.  Chim.  app.,  v,  102 
Strecker;     Ann.  Ch.  Pharem.,  xci,  761 
Trapp;    Jahresb.  1863,  702. 
Wormley ;    Chem.  News,  vol.  ii,  July,  1860 

On  Morphine. 

Anderson ;    Ann.  Ch.  Pharm.,  Ixxv,  80. 

Dupre  ;     Chem.  News,  viii,  267  ;  Jahresb.,  1863,  704. 

Erdmari ;     Ann.  Ch.  Pharm.  cxx,  88  ;  ibid,  cxxii,  360. 

Flandin  ;    Compt,  rend.,  xxxvi,  517. 

Frohde;     Zeitsch.  f.  anal.  Chem.  v,  214;  Arch.  f.  Pharm.,  clxxvi, 

Huseman  ;      Ann.  Ch.  Pharm.,  cxxviii,  305. 

Kalkbrunner ;  Zeitsch.  d.  all.  Oest.  Apot.  Ver.,  No.  27. 

Lassaigue ;     Ann.  Ch.  Pharm.  [2]  xxv,  102. 

Lefert;    J.  Pharm.  [3]  xl,  97. 

Mermer;     J.  Chim.,  xxiii,  12. 

Wormley;  Chem.  News,  vol.  ii,  Sept.,  1860. 

On  Strychnine. 

Bingley ;    Chem.  Gaz.,  1856,  229. 

Brieger;    Jahresb.  pr.  Pharm.  xx,  87. 

Cloetta;     Zeirsch.  f.  anal.  Chem.,  v,  265. 

Davy  ;    J.  Pharm.  [3]  xxiv.,  204. 

Djurberg;    Chem  Centralb,  1872,  153 ;  Zeitsch.  f.  anal.  Chem.,  1872, 440. 

Eboli ;  Archiv  der  Pharm.,  cxxxv,  186. 

Erdman  and  Marchand ;     Jour.  f.  prakt.  Chem.,  xxxi,  374. 

Gorup-Besenez ;  Handwbrterb,  [2]  i,  468. 

Graham  and   Hofman ;     Pharm.  Trans.,   xi,  504 ;  Chem.   Gaz.,  1852, 

197 ;  Ann.  Ch.  Pharm.,  Ixxxiii,  39. 
Hagen;     Ann.  Ch.  Pharm.  ciii,  159. 
Hunefeld;     Schw.,  Ix.  454. 
Jansseu ;    Zeitsch.  f.  anal.  Chem.,  4  Jahrgang. 
Jordan  ;    N.  Repert,  x,  156. 
Letheby ;  Pharm.  J.  Trans,  xvi,  10. 
Mack  ;     N.  Br.  Arch.,  xlvi,  314. 
Marchand ;    Chem.  Gaz.,  June  15,  1844 


APPENDIX. 


'75 


Mayer;    J.  Pharm.  [3]  xlvi. 

Reese:     Chera.  News.  1862,  316. 

Rousseau;     J.  Chim.  Me'd.  xx,  415. 

Sonnenschein ;    Jahresb,  1870,1032;  Ber.  d.  Deutsch.  Chem.  Gess. 

iii,  653. 

Schroder  ;     N.  Br.  Arch.,  xciii,  190. 
Thomas  ;     Amer.  Jour.  Pharm.  1862,  227. 
Thompson ;  Pharm.  J,  Trans.,  ix.,  24. 
Vogel ;     N.  Repert  Pharm.,  ii,  560. 

de  Vrij  and  van  der  Burg;     Pharm.  J.  Trans,  xvi,  448. 
Wagner;    Kopp's  Jahresb.,  1861,  857  ;  Zeitsch. f.  anal.  Chem.,  vi,  387. 
Wittstein;     Pharm.  Viertelj.,  vi,  273. 
Wormley ;     Am.  Jour.  Sc.  and  Arts.,  xxviii,  Sept.,  1859. 


On  the  detection  of  Falsifications  of  Writings. 


Lucas;     Chem.  Centralb,  1868,  1517. 

Knecht-Seiiefelder ;     Technol.,  xxvi,  143. 

Moride  ;     Compt.  rend.,  Iviii,  367  ;  Ding,  poly,  Jour,  clxxii,  390. 

Vorwerk;     Ding.  poly.  Jour.,  clxxii,  158. 

;  Berl.  ind.  Z.,  1864,  41. 


On  the  detection  of  adulterations  in  Flour  and  Bread- 


Barral ;     Compt.  rend.,  Ivi,  834. 

Bastelaer;     Chem.  Centralb,  1868,  1342. 

Cailletet;    ibid,  1858,  1392. 

Corput;    ibid,  1860,  207. 

Crooks;     Chem.  News.,  vol.  xxxiii,  73. 

Danckwort ;     Archiv  der  Pharm.  [2]  xx,  47. 

Davis;     Chem.  News,  xxv.,  207. 

Eulenberg  and  Vohl ;     Poly.  Centralb,  cxcvii,  530. 

Gobley;    Jour,  de  Pharm.,  April,  1844. 

Hadon;     Chem.  News,  1862. 

Hager;     Ding.  Poly.  Jour.,  clxxiii,  159. 

Harsley;    Archiv   der  Pharm.,  July    and    Dec.,    1873;  Chem.  News, 

xxv,  230. 

Moitessier;     Annal.  d'Hygiene,  1868. 
Odliug ;     J.  Soc.  Arts,  April  9,  1858. 
Oser;     Ding.  poly.  Jour.,  clxxxiii,  256. 
Rivot;     Ann.  de  Phys.  etde  Chim.,  30  serie  t,  xlvii. 
Rummel ;     Ding.  poly.  Jour.,  cxxxix,  49. 
Tasbender ;     Ding.  poly.  Jour.,  No.  6,  ccvi. 
Wanklyn;  Archiv   der   Pharm.,   Dec.,  1873;  Chem.   News,  xxxiii,  No. 

736;  Ber.  Med.  Jour.,  March  29,  1873. 
8 


I76  LEGAL  CHEMISTRY. 

On  the  examination  of  Fatty  Oil*. 

Behrens ;     Ding.  poly.  Jour.,  cxxxi,  50. 

Calvert;     Pharm.  J.  Trans.,  xiii,  356. 

Clarke  ;     Chem.  News,  xxiii,  145. 

Dingl ;     Poly.  Jour.,  clxxiv. 

Donny ;     Bull.  Soc.  d'Erc,  1864,  372;  Jahresb.,  1864,  734. 

Dragendorff ;     Pharm.  Zeitsch.  f.  Russl.,  ii,  434. 

Fluckiger;     Chem.  Centralb,  1871,  55. 

Glassner  ;     (trans.)  Am.  Chem.,  Dec.,  1873. 

Gobley;    J.  Pharm.  [3],  iv,  285;  ibid.  v.  67. 

Jacobson ;     Bull.  Soc.  Chim.,  [2]  vii,  96. 

Langlies;    Zeitsch.  f.  anal.  Chem.,  1870,  534. 

Ludwig;     Archiv  der  Pharm.,  [3]  i,  I. 

MacNaught;     Chem.  Centralb,  1862,  742. 

Massie;    Zeitsch.  f.  anal.  Chem.,  1871,  495. 

Maumene;     Compt.  rend.,  xxxv,  572. 

Nickles;    Bull.  Soc.  Chim.,  [2]  vi,89 

Penot;    Bull,  de  Mullh.,  xxvi,  7  ;  Jahresb.,  1866,  827. 

Roth;    Bull,  de  Mullh.,  1864,  104. 

Ure's  Diet,  of  Arts,  etc.,  iii,  300. 

Vogel ;    Chem.  Centralbl,  1863,  945. 

"Watt's  Diet,  of  Chem.,  iv.,  182. 

On  the  examination  of  -Tlilk. 

Boussingault ;    Ann.  Chem.  Phys.  [4]  xxv,  382. 

Baumhauer;    J.  pr.  Chem.,  Ixxxiv,  145. 

Casselman  ;     Chem.  Centralb,  1863,  689. 

Dancer;     Chem.  News,  v,  21,  p.  51. 

Daubrawa ;    Jour,  f .  prakt.  Chem.,  Ixxviii,  426. 

Donne;     Compt.  rend.,  xvii,  pp.  585,  591. 

Filhol  and  Joly ;     Wurtz's  Diet,  de  Chim.,  t.  ii,  p.  195. 

Gmelin ;     Handb.  der  Chem.,  viii,  [2]  246-273. 

Heeren;     Chem.  Centralb,  1870,304. 

Hermstaedt;     Pharm.  Centralb,  1833,401, 

Kletzinsky ;    Chem.  Centralb.,  1861,  244. 

Lade  ;     Chem.  Centralb,  1858,  144. 

Leconte ;    ibid,  1854,  1465. 

Lehman ;    Lehrb.   der   Phys.   Chem.,  1863,  ii,  pp.  287,  301 ;  (trans,  by 

Day)  ii,  pp.  449,  475. 

Macadams;     Am.  Chem.,  May,  1875,  4J9- 
Marchand ;    Jour,  de  Pharm.,  Nov.,  1854. 
Michaelson ;    Ding.  poly.  Jour.,  cxlix,  59. 
Millon ;  Compt.  rend.,  lix,  396. 
Muller ;     Zeitsch.  f.  anal.  Chem.,  No.  3,  1872. 
Otto;     Ann.  Chem.  Pharm.,  cii,  47. 
Pelouze  and  Fremy ;    Traite  de  Chim.  gen.,   [2  edit.]  Paris,  1857, 

p.  195. 


APPENDIX.  177 

Fribram ;    Dings,  poly.  Jour.,  cxcvii,  448 
Reichelt;  Bayr.  K.  u.  Gwbl.,  1859,  602. 
Reineck  ;     Ding.  poly.  Jour.,  cci,  433. 
Rosenthal ;     Chem.  Centralb,  1854,  1392. 
Seely  ;  Sill.  Am.  J.,  vii,  293. 

Veriiois  and  Becqueret ;     Ann.  d'Hygiene,  April,  1853. 
Voelcker;     Am.  Chem.,  May,  1875,  p.  412. 
Vogel;  Poly.  Notizbl.,  No.  10,  1874. 

Wanklyn;  Pharm.  Viertelj.,  xx,  201:  Milk  Jour.,  i,  109.160;  Chem.  News, 
xxviii,  No.  623;  ibid,  No.  736;  Pharm.  Journ.  Trans.,  [3]  i,  605. 

Oil  the  detection  of  adulteration  iu  Wine  and  Beer. 

WINE. 

Beck;     Edinb.  Phil.  Jour.,  1835 

Berthelot  and  Fleurien  ;     Compt.  rend.,  Ivii,  394. 

Blume;     Dings,  poly.  Jour.,  clxx,  240. 

Bolly  and  Paul;  Manual  of  Tech.  Anal.,  p.  331. 

Boyer  and  Coulet ;     Compt.  rend.,  Ixxvi,  585. 

Brande  ;     Phil.  Trans,  1811. 

Cotlini;     Ann.  du  Genie  Civil,  No.  3,  1873. 

Cotlini  and  Fantazini  ;     Ann.  di  Chim.    Appl.  alia  Medi.,  Juli,  1870. 

Christison ;     Edinb.  Phil.  Jour.,  1838. 

Diez;     Ann.  Ch.  Pharm.,  xcvi,  304. 

Duclaux ;     Ann.  de  Chim.    et   de  Phys.,  July  and   Sept.,  1874 ;  Compt. 

rend.  Ixxviii,  1159. 

Duffield;  Am.  Jour.  Pharm.,   Mar.  1862. 
Dupre ;  Chem.  Soc.  Jour,  xx,  493. 
Fanteuelle ;  J.  Chim.  Med.,  iii,  332. 
Faure;    J.  Pharm,,  vii,  200. 
Fischern;     Ann.  Chem.  Pharm.,  Iviii,  705. 
Fresenius;     ibid,  Ixiii,  384. 
G-eiger;     Mag.  f.  Pharm.,  xix,  266. 
Geromont;     Ann.  Ch.  Pharm.,  xvii,  158. 
Hager;  Zeitsch.  f.  anal.  Chem.,  1872,  337. 
Hitchcock;     Edinb.  Phil.  Jour.,  xxxvii,  176. 
Jacquemin;     Ann.   de  Chim.  et  de  Phys.   v,  s6rie,  Nov.,  1874 ;  Compt. 

rend.,  Ixxix.  523. 

Kersting;  Ann.  Ch.  Pharm.,  Ixx,  50. 
Khol;     T-  Chim.  Med.,  [4]  ii,  251. 

Liebig,  Poggendorff  and  Wohler ;     Handworterb.  ix,  676. 
Ludersdorf ;    J.  f.  prak.  Chem.,  xxiv,  102. 

Maisch;  Proc.  Am.  Pharm.  Assn.,  1863,  296-  1864,  291 ;  1866,  267. 
Mallard;  J.  Chim.  Med.,  iii,  326. 
Maumene ;  Bull.  Soc.  Chim.,  xxii,  No.  i. 
Miller ;     Jour,  de  Pharm.  et  de  Chim.,  Mar.,  1873. 
Mitis  ;     Baierisch.  K.  u.  Gewerbeblatt,  1838. 


1 78  LEGAL  CHEMISTRY. 

Fhipson;  Zeitsch.  f.  anal.  Chem.,  ix,  121. 
Reimau's  Farb.  Zeit.,  Nos.  14-15.  1874. 
Romei ;     Mon.  Scien.,  iii,  t.  iii,  No.  382. 
Salleron ;     Compt.  rend.,  Ixxviii,  No.  16. 
Scheitz ;     Arch.  Pharm.,  [3]  v,  331. 
Schubert;     Pogg.  Annal.,  Ixx,  397. 
Sestini ;     Landwirthsch.  Ver.  Stat.,  xv,  9. 
Tuchschmeidt ;  Jahresb.,  1871,967. 
Zierl;     Baierisch.  Kunst.  Gewerbebl,  1838. 

BEER. 

Bias ;    Viertelj.  f.  prakt.  Pharm.,  xxi,  584. 

Bruuner ;    Archiv   der    Pharm.,   April,    1873 »  Dings,  poly.  Jour.,  ccix, 

No.  6;  Jour,  de  Pharm.  et  de  Chim.,  Sept.,  1873  '•>  Poly-  Nolizblatt, 

No.  17,  1873. 

Dietz ;     Neues  Jahresb.  f.  Pharm,,  xxxix,  No.  i. 
Dragendorf f ;     Archiv.    der     Pharm.,   April   and   May,    1874;    Dings. 

poly.  Jour.,  ccxiv,  pp.  33,  389. 
Dullo  ;    Wieck's  Gaz.,  1865,  64. 
Gunckel;     Arch.  f.  Pharm,  clxiv. 
Kubinki;    Le   Technol,    No.   397;  (trans.)  Amer.  Chem.,   Nov.,  1874; 

Dings,  poly.  Jour,  ccxi,  360. 
Langley;  Chem.  Centralb,  1865,  184. 
Meme ;    Compt.  rend.,  2  me  sem.,  No.  123. 
Michaelis;    111.  Gewerbz,  1871,  8. 
Muspratt'a  Chem.  i,  281. 
Pohl ;     Wiener  Akad.  Ber.  xii,  88. 
Ritter;     Pharm.  Zeitsch.  f.  Russl.,  i,  pp.  304,  414. 
Shafhauel;     Ding.  poly.  Jour.,  cxxxii,  299. 
Schmidt ;    Jour.  f.  prakt.  Chem.,  Ixxxvii,  344. 
Stolber ;     ibid,  xciv,  iii. 
Ure's  Diet.  Chem.,  4th  edit.,  1831,  p.  203. 
Vogel  and  Hammon's  Mitth,  1860,  184. 
Wittstein;    Archiv  der  Pharm.,  Jan.  1875. 

On  the  testing  of  Vinegar. 

Bussy  and  Buignet ;    Jahresb.,  1865,  69. 

G-reville  ;     Ding.  poly.  Jour.,  cxxxi,  139. 

Liebig,  Foggendorff  and  Wohler ;    Handworterb,  ii,  867 

Mohr;     Ann.  Ch.  Pharm.,  xxxi,  277. 

Mollerat ;    Ann.  Chim.  Ixviii,  88. 

Nicholson;     Ding.  pol.  Jour.,  cxxxix,  441. 

Otto ;     Ann.  Chem.  Pharm.,  cii,  69. 

Roscoe;    Chem.  Soc.  Jour.,  xv,  270. 

Runge;    Gewz.  Bayer.  1871,  4. 


APPENDIX,  179 

Strohl;    Jour,  de  Pharm.  et  de  Chi'm.,  Sept.,  1874. 
Toorii;    Jour.  f.  Chem.,  vif  171. 
Wagner;     Chem.  Tech.,  (English  trans.)  p.  467. 
Williams  ;  Pharm.  J.  Trans.,  xiii,  594. 

On  the  detection  of  adulterations  in  Sulphate  of  Quinine. 

Delondre  and  Henry ;    J.  Pharm.,  [3]  xxi,  281. 

Gmelin's  Handbuch,  xvii,  280. 

Guibourt ;    J.  Pharm.,  [3]  xxi,  47.  / 

Henry;     ibid,  xiii,  107. 

Hesse;     Ann.  Ch.  Pharm.,  cxxxv,  325;  Jahresb.,  1865,  441. 

Korner;     Zeitsch.  f.  Chem.,  J.  i,  150;  Jahresb.  1862,  619. 

Phillips ;     Lond.  Lane.,  i,  820. 

Riegel ;    Jahresb.  £.  Pharm.,  xxv,  340. 

On  the  detection  of  Blood  Stains. 

Barruel;     Ann.  d'Hygiene  pub.,  i.  267;  ibid,  No.  6,  1829. 

Bertolet:     Am.  Jour.  Med.,  Sc.,  Jan.,  1874, 

Brucke;    Jahresb.,  1857,  609. 

Van  Been  ;     Zeitsch.  f.  anal.  Chem.,  ii,  459. 

Erdmaii ;     Jour.  pr.  Chem.,  Ixxxv,  i ;  Jahresb.,  1862,  634. 

Falck  ;     Ber.  Klinisch.  Wochb.,  1872. 

van  Geuus  and  Gunning;     Zeitsch.  f.  anal.  Chem.,  1871,  508. 

Gwosden ;     Wiener  Akad.  Ber.,  liii,  [2]  683 ;  Jahresb.,  1866,  746. 

Helwig;     Zeitsch.  f.  anal.  Chem.,  1872,  244. 

Hirsch  ;     N.  J.  Pharm.,  xxxii,  140. 

Hoppe-Seyler ;  Med.  Chem.  Unters.,  i,  298;  Jahresb.,  1867,  805. 

Krauss ;    Jahresb.,  1861,792 

Liebig,  Poggendorff  and  Wohler  ;    Handworterb,  iv,  177. 

Iiirrian;     Jahresb.,  1863,  715 

Lowe;     Pharm.  Centralb,  1854,  137. 

Mandl;     Lond.  Lane.,  Dec.  17,  1842,  176. 

Muller;     Zeitsch.  f.  anal.  Chem.,  1872,  iii. 

Orfila;    Jour,   des    Proges   des   Sc.,   iv,   1827;  Archiv.  gen.   de   Me*d., 

Fev.,  1828. 

Papillon  ;     Mon.  Scien.  Ques.,  Jan.,  1874,  59. 
Reynolds ;     Br.  Med.  Jour.,  Jan.  4,  1873. 
Rose;     Jahresb.  der  Pharm.,  ii,  365;  Jahresb.,  1854,  754. 
Roussin ;     Ann.  d'Hyg.  et  de  M£d.  leg.,  1865. 
Scriba,  Simon  and  Buchner ;    Jahresb.,  1859,  706. 
Sonnenschein ;      Jour,     de   Pharm.   et  de    China.,    July,  1874;  Mon. 

Scien.  ii,  370. 

Sorby;     Chem.  News,  1865,  x'>  PP-  l%6,  194,  232,  256. 
Struve;    Zeitsch.  f.  anal.  Chem.,  1872,  29. 
Taylor;    Guy's  Hosp.  Rep.,  1868. 


i8o  LEGAL  CHEMISTRY. 

Wicke  ;     Pharm.  Centralb.  1854,  431. 
Wittstein;     Arch,  der  Pharm.,  ii,  128. 

Zollikopfer  ;    Ann.   d.   Chem.  u.  Pharm.,  xciii,  237  ;  Pharm.  Centralb. 
1855,  217. 

On  the  detection  of  Spermatic  Stains. 

Bayard ;    Ann.  d'Hygiene.  pub.,  1849,  No.  43. 

Renak ;     Diagnostisch.    u.  Pathologisch.  Unters.  Berlin,  1845,  PP-  I48, 

171, 

Schmidt ;    Diagnostik  Verdach.  Flecken,  Leipzig,  1848,  pp.  42-48. 


The  following  are  the  most  important  works  relating  to  poisons 
and  food-adulteration  that  have  been  issued  since  the  publication 
of  the  first  edition  of  this  book  : 

Adam  ;    £tude  sur  les  principales  methodes  d'essai  et  d'analyse  du 
lait.  Paris,  1879. 

Averbeck  ;     Die  Verfalschung  der  Nahrungsmittel. 

Bremen,  1878. 

Bastide  ;     Vins  sophistiques.  Beries,  1876. 

Bauer  ;     Die  Verfalschung  der  Nahrungsmittel.  Berlin,  1877. 

Bell ;     Analysis  and  adulteration  of  food.  1881. 

Binz  ;     Intoxicationen.  Tubingen,  1878. 

Birnbaum  ;     Einfache  Methoden  zur  Prufung  Lebensmittel.       1877. 
Blane  ;     De  la  contrefac.on. 
Bias ;     De  la  presence  de  1'acide  salicylique  dans  les  bierres. 

Paris,  1879. 
Blochman  ;     Ueber  Verfalschung  der  Nahrungsmittel. 

Konigsberg,  1881. 

Blyth  ;     Dictionary  of  Hygiene.  London,  1877. 

Ibid ;  Manual  of  chemistry.  London,  1879. 

Ibid ;     Foods,  composition  and  analysis.  London,  1882. 

Ibid ;     Poisons,  effects  and  detection  of.  London,  1882. 

Boehn ;     Herzgifte. 
Bolley  ;     Manuel  pratique  d'essai  et  de  recherches  chimiques. 

Paris,  1877. 

Bronner  ;     Chemistry  of  food  and  drink.  London. 

Caldwell  ;     Agricultural  chemical  analysis.  N.  Y.,  1879. 

Casper  ;     Handbuch  der  gerichtlichen  Medizin.  Berlin,  1881. 

Church;     Food.  N.  Y.,  1877. 

Cooley's  Practical  receipts. 

Dannehl;     Die  Verfalschung  des  Bieres.  Berlin,  1877. 

Dietzsch  ;     Die  wichtigsten  Nahrungsmittel,  etc.  Zurich,  1878. 


APPENDIX.  !8i 

Dragendorff ;     Recherches  des  substances  ameres  dans  la  biere. 

Paris,  1876. 
Ibid ;    Gerichtlich  chemische  Ermittellung  von  Giften. 

St.  Petersburg,  1876. 

Eisner  ;     Die  Praxis  Nahrungsmittel  Chemikers.          Leipzig,  1880. 
Eulenberg  ;     Handbuch  der  Gewerbe-Hygiene.  Berlin,  1876. 

Palk  ;     Lehrbuch  der  praktischen  Toxicologie.  Stuttgart,  1880. 

Flick  ;     Die  Chemie  im  Dienst  der  6'ffentlichen  Gesundheitspflege. 

Dresden,  1882. 
Fluegge  ;     Lehrbuch  der  hygienischen  Untersuchungsmethoden. 

Leipzig,  1881. 
Focke  ;     Massregeln  gegen  Verfalschung  der  Nahrungsmittel. 

Chemnitz,  1877. 

Fox  ;     Sanitary  examination  of  water,  air,  and  food.  1878. 

Franchini  ;     Palmelle  prodigieuse.  Bologne,  1880. 

Gamgee  ;     Text-book  of  physiological  chemistry.         London,  1880. 
Gaultier  ;     La  sophistication  des  vins.  Paris,  1877. 

Gimlini  ;      Experimentelle   Untersuchung   liber   die  Wirkung   des 
Aconitins.  Erlangen,  1876. 

Goppelsroeder  ;     Sur  1'analyse  des  vins.  Mulhouse,  1877. 

Grandeau  ;     Handbuch  fur  agricultur-chemische  Analysen. 

Berlin,  1880. 

Griessmayer  ;     Die  Verfalschung  der  wichtigsten  Nahrungs-  und 

Genussmittel.  1880. 

Hahn ;     Die  wichtigsten  d.   bis  jetzt   bekannten   Geheimmittel   u. 

Specialitaten.  1876. 

Hausner;     Fabrikation  der  Conserven  und  Conditen.    Leipzig,  1877. 

Hemming ;     Aids  to  forensic  medicine  and  toxicology. 

London,  1877. 

Hilger  ;     Die  wichtigsten  Nahrungsmittel.  Erlangen,  1879. 

Hoffman  ;     Lehrbuch  der  gerichtlichen  Medizin.  Wien,  1880. 

Hoppe-Seyler ;     Physiologische  Cherriie.  Berlin,  1878. 

Husson  ;     Du  vin.  Paris,  1877. 

Ibid ;    Le  lait,  la  creme,  et  le  beurre.  1878. 

Johnson's  Encyclopaedia,  vol.  iv.  p.  752. 

Johnson  ;     Chemistry  of  common  life.  N.  Y.,  1880. 

Judell ;     Die  Vergiftung  mit  Blausaure.  Erlangen,  1876. 

Kensington  ;     Analysis  of  foods.  London,  1879. 

Klencke  ;    lllustrirtes  Lexicon  der  Verfalschung  der  Nahrungsmittel 
und  Getranke.  Leipzig,  1878. 

Koenig  ;  Chemische  Zusammensetzung der  menschlichen  Nahrungs- 
mittel. 

Lang ;     Die    Fabrikation  der    Kunstbutter,   Sparbutter,   und    But- 

terin.  1878. 

Lessner  ;     Atlas  der  gerichtlichen  Medizin.  Berlin,  1883. 

Lieberman  ;     Anleitung   zur   chemischen    Untersuchung    auf    der 

Gebiete  der  Medicinal-polizei.  Stuttgart,  1877. 


182 


APPENDIX. 


Lintner  ;     Lehrbuch  der  Bierbrauerei.  1877. 

Loebner  ;     Massregeln  gegen  Verfalschung  der  Nahrungsmittel. 

Chemnitz,  1877. 

Luerssen  ;     Medicinisch  Botanrk.  Leipzig,  1883. 

Maschka  ;  Handbuch  der  gerichtlichen  Medizin.  Tubingen,  1882. 
Medicus ;  Gerichtlich-chemische  Priifung  von  Nahrungs-  und 

Genussmitteln.  1881. 

Montgomery  ;     Essai  de  Toxicologie.  Paris,  1878. 

Muter  ;     A  key  to  organic  materia  medica.  1879. 

Ogston  ;     Lectures  on  medical  jurisprudence.  London,  1878. 

Palm  ;     Die  wichtigsten  und  gebrauchlichsten  Nahrungsmittel. 

St.  Petersburg,  1882. 

Parkes  ;     Hygiene.  Phila.,  1878. 

Pasteur  ;  Etudes  sur  la  biere.  Paris,  1876. 

Pavy  ;     A  treatise  on  food  and  dietetics.  London,  1875. 

Pennetier  ;     Lecons  sur  les  matieres  premieres  organiques. 

Paris,  1881. 

Praag  ;  Leerbock  voor  practische  Giftleer.  Utrecht. 

Pratt ;     Food  adulteration.  Chicago,  1880. 

Prescott ;     Proximate  organic  analysis.  N.  Y.,  1882. 

Hitter  ;     Des  vins  colorfes  par  la  fuchsine.  Paris,  1876. 

Reitleitner  ;     Die  Analyse  des  Weines.  Wien,  1877. 

Schnacke  ;     Worterbuch  der  Verfalschung.  Jena,  1877. 

Schmidt ;     Anleitung  sanitarisch-  und  polizeilich-chemischen  Unter- 

suchungen.  Zurich,  1878. 

Schroff;     Beitrag  zur  Kenntniss  des  Aconits.  Wien,  1876. 

Selmi  ;  .  Chimica  applicata  all'  igiene  alia  economia  domestica. 

Milan. 

Sharpies  ;  Food  and  its  adulteration.  Preston,  1879. 

Smith  ;     On  foods.  N.  Y.,  1873. 

Smith,  Ed. ;  Manual  for  medical  officers  of  health.  London,  1874. 
Ibid ;  Handbook  for  inspectors  of  nuisances.  London. 

Spon's  Encyclopaedia.  London,  1882. 

Squibb  ;  Proper  legislation  on  adulteration  of  food.  N.  Y.,  1879. 
Steirlin  ;  Ueber  Weinverfalschung  und  Weinfarbung.  Bern,  1877. 
Ibid;  Das  Bier  und  seine  Verfalschung.  Bern,  1878. 

Thudicum  and  Dupre  ;     Wine. 

Vogel ;     Praktische  Spectral-analyse.  Nordlingen,  1877. 

Wanklyn  ;     Tea,  coffee,  and  cocoa.  London,  1874. 

Wanklyn  and  Cooper  ;     Bread  analysis.  London,  1881. 

Wenyl ;     Analytisches  Htilfsbuch.  Berlin,  1882. 

Wittstein  ;  Taschenbuch  des  Nahrungs-  und  Genussmittel  Lehre. 

Nordlingen,  1877. 

Woodman;     Handbook  of  forensic  medicine.  Londons  1877. 

Wurtz  ;    Traite  elementaire  de  chimie  medicale.  Paris. 


APPENDIX. 


MEMOIRS. 

Alkaloids. 

Journal  Chem.  Soc.  i,  1877,  p.  143  ;  ibid,  i,  1878,  p.  151  ;  ibid,  May, 

1882  ;  ibid,  ccxliv,  1883,  p.  358. 
Trans.  Internat'l  Med.  Cong.,  1881,  vol.  i,  p.  472. 
Virch.,  Arch.  bd.  79,  1880,  s.  292  ;  ibid,  bd.  87,  1882,  s.  410. 
Archiv.  d.  Pharm.,  Jan.  7,  1882 ;  ibid,  [3]  vii,  pp.  23-26 ;  ibid,  [3]  vi, 

p.  402. 

Liebig,  Anal.  bd.  708,  1881. 
Berl.  Klin.  Wochenschr.  1876,27. 
Pfliiger's,  23,433. 

Lancet,  Sept.  30,  1880 ;  ibid,  Nov.  28,  1882  ;  ibid,  Nov.  13,  1882, 
Bull.  Farm.  Milano,  1881,  p.  197. 
Zeitsch.  f.  Anal.  Chem.  i,  517. 
Gazett.  Chim.  Ital.  vi,  153-166. 
Pharm.  Zeitschr.  f.  Russland,  i,  p.  277. 
Vierteljahrsschr.  f.  gericht.  Med.  xxiii,  p.  78. 

Arsenic  and  Antimony. 

Archiv.  f.  exper.  Path.  u.  Pharm.  :  Leipzig,  1882. 

Pharm.  Journ.  Trans.  [3]  pp.  81-83. 

Med.  Jahrbuch,  1880. 

Journ.  d'Hygiene,  Juil.,  1878. 

Medical  Times  and  Gaz.  1876,  p.  367. 

Chem.  News,  Jan.,  1881,  p.  21  ;  ibid,  xxxiii.,  pp.  58  and  74. 

Am.  Chem.  Journ.  ii,  No.  4. 

Bull.  Soc.  Chim.  [2]  xxvi,  p.  541  ;  ibid,  Jan.  7,  1877. 

Zeitsch.  f.  Anal.  Chem.  xiv,  pp.  250,  281,  356  ;  ibid,  i,  p.  445. 

Liebig,  Anal,  ccvii,  p.  182. 

Lancet,  1879,  p.  699  ;  ibid,  May  19,  1883. 

Journ.  Chem.  Soc.  No.  i,  1876. 

mercury;  Copper  and  Lead. 

Zeit.  f.  Phys.  Chem.  1882,  i,  p.  495. 

Analyst,  1878,  p.  241. 

Chem.  News,  xxxi,  p.  77  ;  ibid,  xxxi,   p.   801  ;  ibid,  xxxiv,  pp.  176, 

200,  and  313. 

Analyst,  1877,  pp.  13  and  216. 
Journ.  Chem.  Soc.  1876,  ii,  p.  4. 
Dingl.  Pol.  Journ.  ccxx,  446. 
Med.  Gazette,  xlviii,  1047. 


!84  APPENDIX. 

Prusslc  Acid. 

Analyst,  Apr.,  1877,  p.  5. 

Bull.  Gen.  de  Ther.  No.  30. 

Am.  Journ.  Phys.  Sci.,  Arnold,  1869. 

Virch.,  Arch.  f.  Path.  Anat.  bd.  38,  p.  435. 

News  Repert.  f.  Pharm.,  18,  356. 

Journ.  Chem.  Soc.  1876,  i,  p.  112. 

Bericht.  d.  Deutsch.  Chem.  Gess.  ix,  p.  1023. 

Viertelj.  f.  Ger.  Med.  1881,  p.  193. 

Zeit.  f.  Anal.  Chem.  von  Fresenius,  xii,  p.  4. 

Flour  and  Bread. 

Analyst,   June,  1878  ;  ibid,  Jan.,  1882  ;  ibid,  1878,  No.  28  ;  ibid,  vi, 

1879,  p.  126;  ibid,  iii,  pp.  274,  355. 
Chem.  News,  1873,  1879,  xxxix,  p.  80. 
Dingl.  Pol.  Journ.  bd.  209. 
Journ.  Pharm.  [4]  iv,  108. 
Chem.  Centr'b't,  1877,  585. 
Pharm.  Journ.  xiii,  857. 
Journ.  Chem.  Med.  1878,  p.  240. 
An.  d.  Chem.  u.  Pharm.  bd.  10,  45  u.  101. 
Journ.  f.  Pract.  Chem.  xcix,  296  ;  ciii,  65,  193,  233,  273. 
Zeit.  Anal.  Chem.  1878,  p.  440  ;  ibid,  1879,  v°l-  xviii,  p.  I2O. 
Chem.  Soc  Jour,  xxxv,  p.  610. 
Jour.  d'Hygiene,  May,  1878. 
Pharm.  Jour.  Trans.  1876,  cccxii,  1001. 
Pharmacographia,  1879,  P-  °2- 
Sanitary  Engineer,  vol.  v,  p.  66. 

Tea. 

Pharm.  Journ.  1873;  3d  series,  1874. 
Chem.  News,  xxx,  1874  (Allen)  ;  xxx,  125  ;  xxviii,  186. 
Journ.  Pharm.  [2]  xxvi,  63  ;  xii,  234,  229. 
Analyst,  June,  1877  ;  1876  (Wigner). 
Journ.  Chem.  Soc.  1875,  385,  1217  ;  ix,  321,  33  ;  1858. 
Journ.  f.  Pract.  Chem.  x,  273  ;  xciv,  65  ;  li,  401. 
Bull.  Soc.  Chim.  [2]  xxvii,  199. 
Journ.  de  Pharm.  d'Anvers,  1876,  121. 
Journ.  Pharm.  et  Chim.  3  serie,  1856,  xxiv,  228. 
Repert.  de  Pharm.  1856,  vii,  p.  117. 
Journ.  Chim.  Med.  2  serie,  1844,  x,  459  ;  1844,  24. 
Ann.  Chem.  Pharm.  xxvi,  244  ;  xxix,  271  ;  xxxvi,  93. 
Ann.  Chem.  Pharm.  Ixxxii,  197  ;  cxii,  96  ;  i,  19  ;  1,  231  ;  Ixiii,  201  ; 
Ixix,  120  ;  Ixxi  ;  cxviii,  151. 


APPENDIX.  !85 

Ann.  Chem.  xxv,  63. 

Med.  Press  and  Circular,  1871,  p.  415. 

Kastu.  Arch,  vii,  266. 

Deut.  Chem.  Ges.  Ber.  ix,  1312. 

Parliamentary  papers,  1871. 

Mag   Piiarm.  xix,  45. 

Ann.  Chim.  Phys.  \$\  xi,  138. 

Schweigg,  Journ.  Chem.  Phys.  Ixi,  487  ;  Ixiv,  372. 

Phil.  Mag.  J.  xxiii,  426  ;  xlii,  21. 

Milk. 

Analyst,   1876,    Jan.  and  May;  1877,   p.  82;   No.  21 ;  Sept.,  Dec.; 

1878,  Jan.  ;  p.  249  ;  1880,  Mar. 
Chem.  News,  1879. 

Journ.  Chem.  Soc.  clxxxix,  Sept.,  1878. 
Comptes  Rendus,  t.  82,   1876. 
Ann.  Chem.  Pharm.  Ixi,  221. 
Milch  Zeit.  1870,  1884. 

Wine  and  Beer. 

Analyst,  1877,  pp.  26,  99,  146,  148. 

Ann.  Chim.  Phys.  [5]  ii,  pp.  233-289. 

Bull.  Soc.  Chim.  [2]  xxv. 

Deut.  Chem.  Ges.  Ber.  ix,  1900. 

Comptes  Rendus,  Ixxxiv,  348. 

Journ.  Chim.  Med.  t.  ix,  p.  495. 

Arch.  Pharm.  [3]  v.  25,  23,  bd.  185,  p.  225. 

Chem.  Soc.  Journ.  ii,  1877,  p.  372. 

Ann.  d'Hyg.  et  Med.  Leg.  1861,  xvii,  pp.  33,  430. 

Vinegar. 

Analyst,  Hi,  1878,  p.  268  ;  i,  1877,  p.  105. 
Ann.  d'Hyg.  et  Med.  Leg.  2  ser.  t.  xii. 
Pharm.  Journ.,  Jul.  3,  1875. 


Within  the  last  few  years  the  subject  of  food-adultera- 
tion has  been  so  prominently  brought  before  the  public 
that,  in  many  instances,  the  various  State  Boards  of  Health 
have  commissioned  their  chemists  to  furnish  reports  on 


,86  APPENDIX. 

this  subject.  These  may  be  found  in  the  annual  pub- 
lications of  the  same,  notably  in  the  volumes  issued  by  the 
Massachusetts,  Michigan,  New  Jersey,  and  New  York  State 
Boards  of  Health.  It  may  also  be  mentioned  in  this  con- 
nection that  the  Sanitary  Engineer  of  New  York,  the  Ana- 
lyst of  London,  the  Zeitschrift  fiir  Untersuckung  von  Lebens- 
mitteln,  Eichstatt,  and  the  Zeitschrift  gegen  Verfdlschung  der 
Lebensmittel,  Leipzig,  are  journals  devoted  to  the  considera- 
tion of  adulterations  and  the  more  recent  methods  em- 
ployed for  their  detection. 

J.  P.  B. 


INDEX. 


Acetic  Acid,  49,  89 
Acids,  46,  95 

Acetic,  49,  89 

Boric,  90 

Formic,  89 

Hydriodic,  go 

Hydrobromic,  90 

Hydrochloric,  46 

Hydrocyanic,  50 

Hydrofluoric,  88 

Hydrosulphuric,  91 

Nitric,  47,  83 

Oxalic,  49,  88,  89,  93 

Phosphoric,  48,  90,  95 

Phosphorous,  45 

Sulphuric,  47,  89,  95 
Aconitine,  79 

Alcoholmeter  (Gay-Lussac's),  145 
Alkalies,  52,  93 

Ammonia,  50 

Baryta,  54 

Lime,  53 

Potassa,  53 

Soda,  53 

Strontia,  54 
Alkaloids,  65 

Aconitine,  79 

Aniline,  75 

Aricine,  77 

Atropine,  80 


Beberine,  76 

Brucine,  78 

Cinchonine,  78 

Codeine,    80 

Colchitine,  80 

Conine,  75 

Delphine,  78 

Digitaline,  80 

Emetine,  80 

Morphine,  So 

Narcotine,  77 

Nicotine,  75 

Papaverine,  77 

Picrotoxine,  80 

Quinine,  77 

Solanine,  79 

Strychnine,  78 

Veratrine,  77 
Alkaloids,separation  of,  by  Stas's  method,  65 

Separation  of,  by  Otto's  method,  69 

Separation  of,  by  v.  Uslar  and  Erdman'a 
method,  70 

Separation  of,  by  Rodgers  &  Girdwood's 
method,  71 

Separation  of,  by  Prollius's  method,  72 

Separation  of,  by  Graham  &  Hof man  3 
method,  73 

Separation  of,  by  Dialysis,  74 
Alkaloids,  identification  of,  74 
Alloys,  examination  of,  112 
Alum  in  flour  and  bread,  126 
Aniline,  75 


188 


INDEX. 


Antimony,  30,  62,  93 

Detection  of,  by  Flandin  and  Danger's 

method,  32 
Detection  of,  by  Naquet's  method,  34 

Aricine,  77 

Arsenic,  17,  60,  93 

Detection  of,  by  the  method  used  prior 

to  Marsh's  test,  17 
Detection  of,  by  Marsh's  test,  21 
Detection  of,  by  Raspail's  test,  29 
Detection  of,  by  Reinsch's  test,  30 

Arsenic,  estimation  of,  21 

Ashes,  examination  of,  104 

Atropine,  80 

B. 

Barley  meal  in  flour,  117 

Baryta,  54  . 

Barreswil's  test  for  milk,  140 

Berberine,  76 

Bicarbonate  of  soda  in  milk,  141 

Bismuth,  62 

Blood  stains,  detection  of,  150 

Bleaching  of  hair,  98 

Boric  acid,  90 

Boutigny's  examination  of  fire-arms,  100 

Bromine,  55,  90,  93,  94 

Briicke's  test  for  blood  stains,  152 

Brucine,  78 

Buckwheat  in  flour,  117,  120 


Cadmium,  63 

Carbonate  of  lime  and  magnesia  in  flour,  125 

Cerebral  substances  in  milk,  143 

Chalk  in  milk,  141 

Chlorine,  54 

Chromium,  64 

Cinchonine  in  sulphate  of  quinine,  149 

Codeine,  80 

Conine,  75 

Coins,  examination  of,  112 

Colchicine,  80 

Copper,  62,  63 

Corn  meal  in  flour,  117,  no 


D. 

Darnel  in  flour,  121 

Delphine,  78 

Determinative  tests  for  poisons,  94 

Digitaline,  80 

Dusart's  test  for  phosphorus,  40 

Dialysis,  15,  74 

Dyeing  of  hair,  97 

E. 

Emetine,  80 

Emulsion  of  almonds  in  milk,  141 

F. 

Fire-arms,  examination  of,  100 

Weapons  provided  with  a  flint,  100 
Weapons  not  provided  with  a  flint,  103 

Fixed  Oils,  examination  of,  128 
Hempseed,  130 
Olive,  128 

Flandin  and  Danger's  test  for  antimony,  32 

Flandin  and  Danger's  test  for  mercury,  37 

Food  (flour  and  bread),  114 

Examination  of  the  gluten,  116 
Examination  of  the  starch,  118 
Examination  of  the  ash,  124 

Formic  acid,  89 

Fresenius  &  Neubauer's  test  for  phospho- 
rus, 42 

G. 

Galactoscope,  138 

Graham  and  Hofman's  method   for  alka- 
loids, 73 

Ground  bones  in  bread  and  flour,  125 
Gum  arable  in  milk,  141 
Gum  tragacanth  in  milk,  141 

H. 

Haemin  crystals^  150 
Hair,  examination  of,  96 
Hempseed  oil,  130 
Hoppe-Seyler's  test  for  blood,  151 
Hydriodic  acid,  90 
Hydrobromic  acid,  90 
Hydrochloric  acid,  46,  91 


INDEX. 


189 


Hydrocyanic  acid,  50 
Hydrofluoric  acid,  88 
Hydrosulphuric  acid,  91 

I. 

Iodides,  90,  94 

Iodine,  56,  94 

Indicative  tests  for  poisons,  36 

L. 

Lactodensimeter,  138 

iactometer,  139 

Lactoscope,  138 

Lassaigne's  test  for  writings,  107 

Lead, 57 

Legumens  in  flour,  117,  121,  124 

Lentils  in  flour,  123 

Lime,  53 

Lime  in  flour,  126 

Linseed  meal  in  flour,  120 

M. 

Macadam's  method  for  alkaloids,  73 
Magnesia  in  sulphate  of  quinine,  148 
Mannite  in  sulphate  of  quinine,  148 
Marchand's  test  for  milk,  139 
Marsh's  test  for  arsenic,  21 
Mercury,  36,  62,  93 

Detection  of,  by  Smithson's  pile,  36 

Detection  of,  by  Flandin  and  Danger's 

method,  37 
Metals,  56 

Antimony,  30,  62,  93 

Arsenic,  17,  60,  93 

Bismuth,  62 

Cadmium,  63 

Chromium,  64 

Copper,  62,  63 

Lead,  57 

Mercury,  36,  62,  93 

Silver,  57 

Tin,  56,  61 

Zinc,  64 

Milk,  examination  of,  137 
Mineral  substances,  in  flour  and  bread   124 

In  milk,  141 

In  sulphate  of  quinine,  148 


Mistcherlich's  test  for  phosphorus,  40 
Morphine,  80 

N. 

Naquet's  test  for  antimony,  34 
Narcotine,  77 
Nicotine,  75 
Nitric  acid,  47,  88 

o. 

Oatmeal  in  flour,  117 

Oleometer,  128 

Olive  oil,  128 

Orfila's  test  for  phosphorus,  39 

Organic  matter 

Destruction  of,  by  aqua  rcgia,  14 
Destruction  of,  by  chlorate  of  potassa, 

J3 

Destruction  of,  by  chlorine,  13 
Destruction  of,  by  nitrate  of  potassa,  10 
Destruction  of,  by  nitric  acid,  8 
Destruction  of,  by  potassa  and  nitrate 

of  lime,  12 
Destruction  of,   by  potassa  and  nitric 

acid,  12 
Destruction  of,  by  sulphuric  acid,  9 

Otto's  method  for  alkaloids,  69 

Oxalic  acid,  49,  88,  89,  95 

P. 

Papaverine,  77 

Payen's  test  for  vinegar,  147 

Phosphoric  acid,  48,  90,  95 

Phosphorous  acid,  45 

Phosphorus,  39,  95 

Detection  of,  by  Orfila's  method,  39 
Detection  of,  by  Mistcherlich's  method, 

40 

Detection  of,  by  Dusart's  method,  40 
Detection  of,  by  Fresenius  and  Neu- 

bauer's  method,  42 
Estimation  of,  45 

Picrotoxine,  80 

Plaster  in  flour,  126 


190 


INDEX. 


Poisons,  detection  of 

In  cases  where  no  clew  exists,  83 
In  cases  where  a  clew  exists,  17 
Destruction  of  the  organic  matter,  8 
Indicative  tests,  86 
Determinative  tests,  94 

Potato  meal  in  flour,  118 

Potassa,  53,  93 

Prolhus'  method  for  alkaloids,  73 

Prussicacid,  50 


Quinine,  77 


Q. 


R. 


Raspail's  test  for  arsenic,  29 
Reinsch's  test  for  arsenic,  30 
Reveil's  test  for  vinegar,  148 
Rice  meal  in  flour,  120 
Robin's  method  for  spermatic  stains,  160 
Rodgers  and  Girdwood's  method  for  alka- 
loids, 71 
Rye  meal  in  flour,  117, 120 

S. 

Salicine  in  sulphate  of  quinine,  148 
Sand  in  flour,  125 
Silver,  57 

Smithson's  pile,  36 
Soda,  53,  92,  93 
Solanine,  79 
Spermatic  stains,  detection  of,  158 


Spermatozoa,  159 
Starch  in  sulphate  of  quinine,  148 
Stearic  acid  in  sulphate  of  quinine,  148 
Stas's  method  for  alkaloids,  65 
Strychnine,  78 
Sugar  in  milk,  142 
Sugar  in  sulphate  of  quinine,  148 
Sulphate  of  copper  in  bread,  127 
Sulphate  of  quinidine  in  sulphate  of  qui- 
nine, 149 

Sulphate  of  quinine,  examination  of,  148 
Sulphuretted  hydrogen,  91 
Sulphuric  acid,  47,  89,  95 
Sympathetic  inks,  tests  for,  no 


Tea,  130 
Tin,  56,  61 


T. 


U. 


v.  Uslar  and  Erdman's  method  for  alka- 
loids, 70 

V. 

Veratrine,  77 
Vinegar,  examination  of,  147 

W. 

Wines,  examination  of,  142 
Writings,  examination  of,  105 


Zinc,  64 


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MORRIS,  E.— Easy  Rules  for  the  Measurement  of  Earthworks, 

by  Means  of  the  Prismoidal  Formula. 
78  illustrations.    8vo,  cloth 1  50 

MORRIS,  Gen.  WM.  H.— Field  Tactics  for  Infantry. 

Illustrated.     18mo,  cloth 75 


Infantry  Tactics. 


2  vols.  24mo 2  00 

2  vols.  in  one,  cloth ...     1  50 


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